natural number
In mathematics, the natural numbers are those numbers used for counting (as in "there are ''six'' coins on the table") and ordering (as in "this is the ''third'' largest city in the country").
Numbers used for counting are called ''cardinal ...
following 39 and preceding 41.
Though the word is related to "four" (4), the spelling "forty" replaced "fourty" in the course of the 17th century and is now the standard form.
In mathematics
*Forty is a
composite number
A composite number is a positive integer that can be formed by multiplying two smaller positive integers. Equivalently, it is a positive integer that has at least one divisor other than 1 and itself. Every positive integer is composite, prime, ...
, a
refactorable number
A refactorable number or tau number is an integer ''n'' that is divisible by the count of its divisors, or to put it algebraically, ''n'' is such that \tau(n)\mid n. The first few refactorable numbers are listed in as
: 1, 2, 8, 9, 12, 18, ...
, an
octagonal number
An octagonal number is a figurate number that represents an octagon. The octagonal number for ''n'' is given by the formula 3''n''2 - 2''n'', with ''n'' > 0. The first few octagonal numbers are
: 1, 8, 21, 40, 65, 96, 133, 176, 225, 280, 34 ...
, and—as the sum of the first four
pentagonal number
A pentagonal number is a figurate number that extends the concept of triangular and square numbers to the pentagon, but, unlike the first two, the patterns involved in the construction of pentagonal numbers are not rotationally symmetrical. The ...
s: —it is a
pentagonal pyramidal number A pyramidal number is a figurate number that represents a pyramid with a polygonal base and a given number of triangular sides. A pyramidal number is the number of points in a pyramid where each layer of the pyramid is an -sided polygon of points. ...
. Adding up some subsets of its divisors (e.g., 1, 4, 5, 10, and 20) gives 40; hence, 40 is a
semiperfect number
In number theory, a semiperfect number or pseudoperfect number is a natural number ''n'' that is equal to the sum of all or some of its proper divisors. A semiperfect number that is equal to the sum of all its proper divisors is a perfect number.
...
.
*Given 40, the
Mertens function
In number theory, the Mertens function is defined for all positive integers ''n'' as
: M(n) = \sum_^n \mu(k),
where \mu(k) is the Möbius function. The function is named in honour of Franz Mertens. This definition can be extended to positive re ...
returns 0. 40 is the smallest number with exactly nine solutions to the equation Euler's totient function .
*Forty is the number of -queens problem solutions for .
*Forty is a
repdigit
In recreational mathematics, a repdigit or sometimes monodigit is a natural number composed of repeated instances of the same digit in a positional number system (often implicitly decimal). The word is a portmanteau of repeated and digit.
Example ...
in ternary (1111, ''i.e.'', , or, in other words, ) and a Harshad number in decimal.
In science
*The
atomic number
The atomic number or nuclear charge number (symbol ''Z'') of a chemical element is the charge number of an atomic nucleus. For ordinary nuclei, this is equal to the proton number (''n''p) or the number of protons found in the nucleus of every ...
of
zirconium
Zirconium is a chemical element with the symbol Zr and atomic number 40. The name ''zirconium'' is taken from the name of the mineral zircon, the most important source of zirconium. The word is related to Persian '' zargun'' (zircon; ''zar-gun'' ...
.
*Negative forty is the unique
temperature
Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measurement, measured with a thermometer.
Thermometers are calibrated in various Conversion of units of temperature, temp ...
at which the
Fahrenheit
The Fahrenheit scale () is a temperature scale based on one proposed in 1724 by the physicist Daniel Gabriel Fahrenheit (1686–1736). It uses the degree Fahrenheit (symbol: °F) as the unit. Several accounts of how he originally defined hi ...
and Celsius scales correspond; that is, −40 °F = −40 °C. It is referred to as either "minus forty" or "forty below".
Astronomy
*
Messier object
The Messier objects are a set of 110 astronomical objects catalogued by the French astronomer Charles Messier in his ''Catalogue des Nébuleuses et des Amas d'Étoiles'' (''Catalogue of Nebulae and Star Clusters'').
Because Messier was only in ...
magnitude
Magnitude may refer to:
Mathematics
*Euclidean vector, a quantity defined by both its magnitude and its direction
*Magnitude (mathematics), the relative size of an object
*Norm (mathematics), a term for the size or length of a vector
*Order of ...
Ursa Major
Ursa Major (; also known as the Great Bear) is a constellation in the northern sky, whose associated mythology likely dates back into prehistory. Its Latin name means "greater (or larger) bear," referring to and contrasting it with nearby Ursa ...
NGC 40
NGC 40 (also known as the Bow-Tie Nebula and Caldwell 2) is a planetary nebula discovered by William Herschel on November 25, 1788, and is composed of hot gas around a dying star. The star has ejected its outer layer which has left behind a sma ...
, a magnitude 12.4
planetary nebula
A planetary nebula (PN, plural PNe) is a type of emission nebula consisting of an expanding, glowing shell of ionized gas ejected from red giant stars late in their lives.
The term "planetary nebula" is a misnomer because they are unrelate ...
The number 40 is found in many traditions without any universal explanation for its use. In
Jewish
Jews ( he, יְהוּדִים, , ) or Jewish people are an ethnoreligious group and nation originating from the Israelites Israelite origins and kingdom: "The first act in the long drama of Jewish history is the age of the Israelites""The ...
* Enki ( /ˈɛŋki/) or Enkil (Sumerian: dEN.KI(G)𒂗𒆠) is a god in Sumerian mythology, later known as Ea in Akkadian and Babylonian mythology. He was originally patron god of the city of
Eridu
Eridu (Sumerian language, Sumerian: , NUN.KI/eridugki; Akkadian language, Akkadian: ''irîtu''; modern Arabic language, Arabic: Tell Abu Shahrain) is an archaeological site in southern Mesopotamia (modern Dhi Qar Governorate, Iraq). Eridu was l ...
, but later the influence of his cult spread throughout
Mesopotamia
Mesopotamia ''Mesopotamíā''; ar, بِلَاد ٱلرَّافِدَيْن or ; syc, ܐܪܡ ܢܗܪ̈ܝܢ, or , ) is a historical region of Western Asia situated within the Tigris–Euphrates river system, in the northern part of the ...
Hittites
The Hittites () were an Anatolian people who played an important role in establishing first a kingdom in Kussara (before 1750 BC), then the Kanesh or Nesha kingdom (c. 1750–1650 BC), and next an empire centered on Hattusa in north-centra ...
and Hurrians. He was the deity of crafts (gašam); mischief; water, seawater, lake water (a, aba, ab), intelligence (gestú, literally "ear") and creation (Nudimmud: nu, likeness, dim mud, make bear). He was associated with the southern band of constellations called stars of Ea, but also with the constellation AŠ-IKU, the Field (
Square of Pegasus
Pegasus is a constellation in the northern sky, named after the winged horse Pegasus in Greek mythology. It was one of the 48 constellations listed by the 2nd-century astronomer Ptolemy, and is one of the 88 constellations recognised today.
W ...
). Beginning around the second millennium BCE, he was sometimes referred to in writing by the numeric ideogram for "40", occasionally referred to as his "sacred number".
A large number of myths about Enki have been collected from many sites, stretching from Southern Iraq to the Levantine coast. He figures in the earliest extant cuneiform inscriptions throughout the region and was prominent from the third millennium down to Hellenistic times.
The exact meaning of his name is uncertain: the common translation is "Lord of the Earth": the Sumerian en is translated as a title equivalent to "lord"; it was originally a title given to the High Priest; ki means "earth"; but there are theories that ki in this name has another origin, possibly kig of unknown meaning, or kur meaning "mound". The name Ea is allegedly Hurrian in origin while others claim that it is possibly of Semitic origin and may be a derivation from the West-Semitic root *hyy meaning "life" in this case used for "spring", "running water". In Sumerian E-A means "the house of water", and it has been suggested that this was originally the name for the shrine to the God at Eridu.
Judaism
* In the
Hebrew Bible
The Hebrew Bible or Tanakh (;"Tanach" '' Michael David Coogan, ''A Brief Introduction to the Old Testament: The Hebrew Bible in Its Context'', Oxford, 2008, p. 116
* Rain fell for "forty days and forty nights" during the Flood (Genesis 7:4).
* Noah waited for forty days after the tops of mountains were seen after the flood, before releasing a raven (Genesis 8:5–7).
* Spies were sent by Moses to explore the land of Canaan (promised to the children of Israel) for "forty days" (Numbers 13:2, 25).
* The Hebrew people lived in the lands outside of the promised land for "forty years". This period of years represents the time it takes for a new generation to arise (Numbers 32:13).
* Several early Hebrew leaders and kings are said to have ruled for "forty years", that is, a generation. Examples include Eli (1 Samuel 4:18), Saul (Acts 13:21), David (2 Samuel 5:4), and Solomon (1 Kings 11:42).
* Goliath challenged the Israelites twice a day for forty days before
David
David (; , "beloved one") (traditional spelling), , ''Dāwūd''; grc-koi, Δαυΐδ, Dauíd; la, Davidus, David; gez , ዳዊት, ''Dawit''; xcl, Դաւիթ, ''Dawitʿ''; cu, Давíдъ, ''Davidŭ''; possibly meaning "beloved one". w ...
defeated him (1 Samuel 17:16).
* Moses spent three consecutive periods of "forty days and forty nights" on
Mount Sinai
Mount Sinai ( he , הר סיני ''Har Sinai''; Aramaic: ܛܘܪܐ ܕܣܝܢܝ ''Ṭūrāʾ Dsyny''), traditionally known as Jabal Musa ( ar, جَبَل مُوسَىٰ, translation: Mount Moses), is a mountain on the Sinai Peninsula of Egypt. It is ...
God
In monotheistic thought, God is usually viewed as the supreme being, creator, and principal object of faith. Swinburne, R.G. "God" in Honderich, Ted. (ed)''The Oxford Companion to Philosophy'', Oxford University Press, 1995. God is typically ...
gave the Torah to the Jewish people, in order to learn the Torah from God, and came down on the seventeenth day of Tammuz, when he saw the Jews worshiping the Golden Calf and broke the tablets (Deuteronomy 9:11).
# He went up on the eighteenth day of
Tammuz
Dumuzid or Tammuz ( sux, , ''Dumuzid''; akk, Duʾūzu, Dûzu; he, תַּמּוּז, Tammûz),; ar, تمّوز ' known to the Sumerians as Dumuzid the Shepherd ( sux, , ''Dumuzid sipad''), is an ancient Mesopotamian god associated with shep ...
to beg forgiveness for the people's sin and came down without God's atonement on the twenty-ninth day of Av (Deuteronomy 9:25).
# He went up on the first day of
Elul
Elul ( he, אֱלוּל, Standard ''ʾElūl'', Tiberian ''ʾĔlūl'') is the twelfth month of the Jewish civil year and the sixth month of the ecclesiastical year on the Hebrew calendar. It is a month of 29 days. Elul usually occurs in August ...
and came down on the tenth day of
Tishrei
Tishrei () or Tishri (; he, ''tīšrē'' or ''tīšrī''; from Akkadian ''tašrītu'' "beginning", from ''šurrû'' "to begin") is the first month of the civil year (which starts on 1 Tishrei) and the seventh month of the ecclesiastical year ...
, the first
Yom Kippur
Yom Kippur (; he, יוֹם כִּפּוּר, , , ) is the holiest day in Judaism and Samaritanism. It occurs annually on the 10th of Tishrei, the first month of the Hebrew calendar. Primarily centered on atonement and repentance, the day' ...
, with God's atonement (Deuteronomy 10:10).
* A mikvah consists of 40 ''
se'ah
The ''se'ah'' or ''seah'' ( he, סאה ''sə’āh''), plural ''se'im'', is a Unit of measurement, unit of dry measure of ancient origin found in the Bible and in Halakha (Jewish law), which equals one third of an ''ephah'', or ''bath (unit), bath ...
'' (approximately ) of water
* The prophet
Elijah
Elijah ( ; he, אֵלִיָּהוּ, ʾĒlīyyāhū, meaning "My El (deity), God is Yahweh/YHWH"; Greek form: Elias, ''Elías''; syr, ܐܸܠܝܼܵܐ, ''Elyāe''; Arabic language, Arabic: إلياس or إليا, ''Ilyās'' or ''Ilyā''. ) w ...
had to walk 40 days and 40 nights before arriving at
mount Horeb
Mount Horeb (Hebrew: ''Har Ḥōrēḇ''; Greek in the Septuagint: ; Latin in the Vulgate: ') is the mountain at which the Ten Commandments were given to Moses by Yahweh, according to the Book of Deuteronomy in the Hebrew Bible. It is describe ...
(1 Kings 19:8).
* 40 lashes is one of the punishments meted out by the
Sanhedrin
The Sanhedrin (Hebrew and Aramaic: סַנְהֶדְרִין; Greek: , ''synedrion'', 'sitting together,' hence ' assembly' or 'council') was an assembly of either 23 or 71 elders (known as "rabbis" after the destruction of the Second Temple), ...
( Deuteronomy 25:3), though in actual practice only 39 lashes were administered.
* (Numbers 14:33–34) alludes to the same with ties to the prophecy in The Book of Daniel. "For forty years—one year for each of the forty days you explored the land—you will suffer for your sins and know what it is like to have me against you."
* One of the prerequisites for a man to study Kabbalah is that he is forty years old.
* "The registering of these men was carried on cruelly, zealously, assiduously, from the rising of the sun to its going down, and was not brought to an end in forty days" (3 Maccabees 4:15).
*
Jonah
Jonah or Jonas, ''Yōnā'', "dove"; gr, Ἰωνᾶς ''Iōnâs''; ar, يونس ' or '; Latin: ''Ionas'' Ben (Hebrew), son of Amittai, is a prophet in the Hebrew Bible and the Quran, from Gath-hepher of the northern Kingdom of Israel (Samaria ...
warns Nineveh that "Forty days more, and Nineveh shall be overthrown." (Jonah 3:4)
Christianity
Christianity similarly uses forty to designate important time periods.
*Moses stays on Mount Sinai for 40 days and nights (Exodus 24:18).
* Before his
temptation
Temptation is a desire to engage in short-term urges for enjoyment that threatens long-term goals.Webb, J.R. (Sep 2014). Incorporating Spirituality into Psychology of temptation: Conceptualization, measurement, and clinical implications. Sp ...
, Jesus fasted "forty days and forty nights" in the
Judean desert
The Judaean Desert or Judean Desert ( he, מִדְבַּר יְהוּדָה, Midbar Yehuda}, both ''Desert of Judah'' or ''Judaean Desert''; ar, صحراء يهودا, Sahraa' Yahuda) is a desert in Palestine and Israel that lies east of Jerusa ...
(Matthew 4:2, Mark 1:13, Luke 4:2).
* Forty days was the period from the
resurrection of Jesus
The resurrection of Jesus ( grc-x-biblical, ἀνάστασις τοῦ Ἰησοῦ) is the Christian belief that God raised Jesus on the third day after his crucifixion, starting – or restoring – his exalted life as Christ and Lo ...
to the
ascension of Jesus
The Ascension of Jesus (anglicized from the Vulgate la, ascensio Iesu, lit=ascent of Jesus) is the Christian teaching that Christ physically departed from Earth by rising to Heaven, in the presence of eleven of his apostles. According to th ...
(Acts 1:3).
* According to Stephen, Moses' life is divided into three 40-year segments, separated by his growing to adulthood, fleeing from Egypt, and his return to lead his people out (Acts 7:23, 30, 36).
* In modern Christian practice,
Lent
Lent ( la, Quadragesima, 'Fortieth') is a solemn religious observance in the liturgical calendar commemorating the 40 days Jesus spent fasting in the desert and enduring temptation by Satan, according to the Gospels of Matthew, Mark and Luke ...
consists of the 40 days preceding
Easter
Easter,Traditional names for the feast in English are "Easter Day", as in the '' Book of Common Prayer''; "Easter Sunday", used by James Ussher''The Whole Works of the Most Rev. James Ussher, Volume 4'') and Samuel Pepys''The Diary of Samuel ...
. In much of Western Christianity, Sundays are excluded from the count, there are 46 days in total of Lent; in Eastern Christianity, Sundays are included.
* The
Forty Martyrs of Sebaste
The Forty Martyrs of Sebaste or the Holy Forty (Ancient/Katharevousa Greek ''Ἅγιοι Τεσσεράκοντα''; Demotic: ''Άγιοι Σαράντα'') were a group of Roman soldiers in the Legio XII ''Fulminata'' (Armed with Lightning) w ...
* Kirk Kilisse, "Forty Churches" (Σαράντα Εκκλησιές) in Eastern Thrace
* Rain fell for "forty days and forty nights" during the Flood (Genesis 7:4).
Islam
*
Muhammad
Muhammad ( ar, مُحَمَّد; 570 – 8 June 632 CE) was an Arab religious, social, and political leader and the founder of Islam. According to Islamic doctrine, he was a prophet divinely inspired to preach and confirm the mo ...
was forty years old when he first received the revelation delivered by the archangel Gabriel.
*
Masih ad-Dajjal
Al-Masih ad-Dajjal (), otherwise referred to simply as the Dajjal, is an evil figure in Islamic eschatology similar to the Antichrist in Christianity, who will pretend to be the promised Messiah, appearing before the Day of Judgment accordin ...
roams around the Earth in forty days, the first day length is like one year, the second day is like one month, the third day is like one week and the next day (until 40th day) is like one day.
* God forbade the Israelites from entering the Holy Land for 40 years to separate them from Musa ( Moses) and his brother.
* Musa ( Moses) spent 40 days on Mount Sinai where he received the 10 commandments.
Yazidism
* In the
Yazidi
Yazidis or Yezidis (; ku, ئێزیدی, translit=Êzidî) are a Kurmanji-speaking endogamous minority group who are indigenous to Kurdistan, a geographical region in Western Asia that includes parts of Iraq, Syria, Turkey and Iran. The ma ...
faith, The Chermera Temple (meaning "40 Men" in the Yazidi dialect) is so old that no one remembers how it came to have that name but it is believed to derive from the burial of 40 men on the mountaintop site.
Funerary customs
* Some Russians, Bulgarians, and Serbs believe that ghosts of the dead linger at the site of their death for forty days. After the forty days, additional prayers are performed at the grave (parastos (парастос) or panihida (панихида)), to escort the soul on its way to God's court.
* Many Christian Filipinos mark the end of the initial mourning period on the fortieth day after death, and have a
Mass
Mass is an intrinsic property of a body. It was traditionally believed to be related to the quantity of matter in a physical body, until the discovery of the atom and particle physics. It was found that different atoms and different eleme ...
said. They believe that the soul remains on the earthly plane for forty days before entering the afterlife, recalling how Christ ascended to heaven forty days after his
Resurrection
Resurrection or anastasis is the concept of coming back to life after death. In a number of religions, a dying-and-rising god is a deity which dies and is resurrected. Reincarnation is a similar process hypothesized by other religions, whic ...
.
Hinduism
* In
Hinduism
Hinduism () is an Indian religion or '' dharma'', a religious and universal order or way of life by which followers abide. As a religion, it is the world's third-largest, with over 1.2–1.35 billion followers, or 15–16% of the global p ...
, some popular religious prayers consist of forty
shloka
Shloka or śloka ( sa, श्लोक , from the root , Macdonell, Arthur A., ''A Sanskrit Grammar for Students'', Appendix II, p. 232 (Oxford University Press, 3rd edition, 1927). in a broader sense, according to Monier-Williams's dictionary, is ...
s or dohas (couplets, stanzas). The most common being the
Hanuman Chalisa
The ''Hanuman Chalisa'' (; ''Chaupai (poetry), Forty chaupais on Hanuman'') is a Hinduism, Hindu devotional hymn (''stotra'') in praise of Hanuman.Rambhadradas 1984pp. 1–8./ref> It was authored by Tulsidas in the Awadhi language, and is his bes ...
(''chaalis'' is the Hindi term for 40).
In the Hindu system some of the popular fasting periods consist 40 days and is called the period One 'Mandala Kalam' Kalam means a period and Mandala Kalam means a period of 40 days. For example, the devotees (male and female) of Swami Ayyappa, the name of a Hindu god very popular in Kerala, India (Sabarimala Swami Ayyappan) strictly observed forty days fasting and visit (since female devotees of a certain biological age group wouldn't be able to perform the continuous 40-day-austerities, they wouldn't enter into the god's temple until September 2018) with their holy submission or offerings on 41st or a convenient day after a minimum 40 days practice of fasting. The offering is called "Kaanikka".
Buddhism
* When discussing meditation, the
Visuddhimagga
The ''Visuddhimagga'' (Pali; English: ''The Path of Purification''), is the 'great treatise' on Buddhist practice and Theravāda Abhidhamma written by Buddhaghosa approximately in the 5th century in Sri Lanka. It is a manual condensing and sys ...
Anand Sahib
The Anand Sahib (Gurmukhi: ਅਨੰਦ ਸਾਹਿਬ ''anada sāhiba'') is a collection of hymns in Sikhism, written in the Ramkali Raag by Guru Amar Das Ji, the third Guru of the Sikhs. It appears on the pages 917 to 922 in Guru Granth Sahi ...
, the fifth and the final of the daily Sikh prayers have 40 paragraphs, and the 40th paragraph is often read when concluding any Sikh ceremony.
*
Chali Mukte
The Battle of Sri Muktsar Sahib (Muktsar) or Battle of Khidrāne Dee Dhāb took place on 29 December 1705, (29 Poh) following the siege of Anandpur Sahib, Anandpur Sahib. In 1704, Anandpur Sahib was under an extended siege by the allied forces ...
(40 liberated ones) refer to the 40 soldiers in the army of Guru Gobind Singh. These 40 disciples were the most favorite and beloved disciples of the Guru.
In entertainment
* "#40" is a song by
Dave Matthews Band
Dave Matthews Band (also known by the initials DMB) is an American rock band formed in Charlottesville, Virginia, in 1991. The band's founding members were singer-songwriter and guitarist Dave Matthews, bassist Stefan Lessard, drummer and bac ...
* "40" is a song by
Franz Ferdinand
Archduke Franz Ferdinand Carl Ludwig Joseph Maria of Austria, (18 December 1863 – 28 June 1914) was the heir presumptive to the throne of Austria-Hungary. His assassination in Sarajevo was the most immediate cause of World War I.
Fr ...
* "40" is a 1983 song by U2 from their album ''War'', whose lyrics are a modification of Psalm 40
*
Crush 40
Crush 40 is a Japanese-American hard rock band. The group consists of guitarist and composer Jun Senoue and vocalist Johnny Gioeli, although Senoue has featured other lead vocalists on a Crush 40 album. Crush 40 is best known for their contri ...
is an American-Japanese hard rock band featured in the '' Sonic the Hedgehog'' franchise produced by Sega and
Sonic Team
is a video game developer owned by the Japanese video game company Sega as part of its Sega CS Research and Development No. 2 division. Sonic Team is best known for the long-running ''Sonic the Hedgehog'' series and games such as '' Nights int ...
; their self-titled album is named after the band.
* The highest number counted to on ''
Sesame Street
''Sesame Street'' is an American educational children's television series that combines live-action, sketch comedy, animation and puppetry. It is produced by Sesame Workshop (known as the Children's Television Workshop until June 2000) ...
''
* The number of positions on several radio countdown programs, notably '' American Top 40'', ''
American Country Countdown
''American Country Countdown'', also known as ''ACC'', is a weekly internationally syndicated radio program which counts down the top 40 country songs of the previous week, from No. 40 to No. 1, according to the ''Billboard'' Country Airplay ch ...
The Early Show
''The Early Show'' is an American morning television show that aired on CBS from November 1, 1999 to January 7, 2012, and the ninth attempt at a morning news-talk program by the network since 1954. The program aired Monday through Friday from ...
'' segment "Chef on a Shoestring".
* Noah Shebib, the Canadian hip hop producer is also known as "40".
* "
Forty Shades of Green
"Forty Shades of Green" is a song about Ireland, written and first performed by American country singer Johnny Cash. Cash wrote the song in 1959 while on a trip to Ireland; it was first released as a A-side, B-side of the song "The Rebel–Johnny ...
", a song about Ireland, was written and recorded by Johnny Cash in 1961.
* '' Fortycoats & Co.'' was an Irish children's television drama series of the 1980s; the name is based on the nickname of a Dublin tramp, Johnny Fortycoats, of the 1930s.
In sports
* In baseball, each team in
Major League Baseball
Major League Baseball (MLB) is a professional baseball organization and the oldest major professional sports league in the world. MLB is composed of 30 total teams, divided equally between the National League (NL) and the American League (AL), ...
is allowed to have 40 players under major-league contracts at any given time (not including players on the 60-day disabled list). From September 1 to the end of the regular season, teams were allowed to expand their game-day rosters to include the entire 40-man roster through the 2019 season, but from 2020 teams are only allowed 28 players on their game-day rosters during that period.
* In horse racing, the maximum permitted number of runners in the
Grand National
The Grand National is a National Hunt horse race held annually at Aintree Racecourse in Liverpool, England. First run in 1839, it is a handicap st ...
is 40.
* The 40-yard dash is an important metric in American football scouting.
* In tennis, the number 40 represents the third point gained in a game. A score of 40–40 (three points each) is called "deuce", at which time a player must score two consecutive points to win the game.
* In NASCAR, the number of cars that have run each race in the top-level NASCAR Cup Series, Cup Series since 2016, and the second-level Xfinity Series since 2013.
In other fields
Forty is also:
* Kyrgyzstan is a country in Central Asia and is derived from the Turkic languages, Turkic word meaning "Land of forty tribes"
*in the expression "forty winks", meaning a short sleep
*in the trademark name of the penetrating oil and water-displacing spray WD-40; "WD-40" is an abbreviation of "Water Displacement, 40th formula".
*the caliber of the bullet in a number of firearms cartridges, most notably the .40 S&W. (The 10mm Auto, although designated as metric caliber, uses the same caliber, and often uses the same bullets.)
*the number of years of marriage celebrated by the ruby wedding anniversary
*the List of country calling codes, code for direct dial international phone calls to Romania
*the number of spaces in a standard Monopoly (game), ''Monopoly'' game board
*the number of thieves in "Ali Baba and the Forty Thieves" and in ''Ali Shar and Zumurrud'', from ''One Thousand and One Nights'' (both the numbers 40 and 1001 (number), 1001 are more likely to mean "many" than to indicate a specific number)
*the customary number of hours in a regular Working time, workweek in some Western world, Western countries
*the number of weeks for an average term of pregnancy, counting from the woman's last menstrual period
*a 40 (malt liquor), 40-ounce bottle of malt liquor, referenced in the song "40oz. to Freedom" by Sublime (band), Sublime
*The ''Tessarakonteres'', or 40, the largest ship of antiquity, constructed by Ptolemy IV
*Forty is the only integer whose English name has its letters in alphabetical order.
*Forty Foot, a promontory on the southern tip of Dublin Bay, Ireland, from which people have been swimming in the Irish Sea all year round for some 250 years
*After the Civil War, there were plans to offer freed slaves 40 acres and a mule.
*To understand a people, you must live among them for 40 days. ''~Arabic proverb''
*Quarantine, the practice of isolation to prevent the spread of epidemic disease, derives from a Venetian dialect of the Italian meaning 'forty days', the period that ships were required to be isolated before passengers and crew could go ashore during the Black Death.
*To qualify for retirement benefits under Social Security (United States), a person must have earnings for 40 quarters (equivalent to 10 years).
*Forty-shilling freeholders, a nickname, given to those who qualified for a Suffrage, franchise, the right to vote, based on their interest in land and/or property with an annual rental value of 40s. Introduced in England in 1430, it applied there and in many associated territories, in various forms, up to 1918.
See also
* List of highways numbered 40
*Yaldā Night, also known as Shab-e Chelleh, meaning "night of forty", celebrated in Iran on the night of the Northern Hemisphere's December solstice, winter solstice
