Iota (; uppercase Ι, lowercase ι; ) is the ninth letter of the
Greek alphabet
The Greek alphabet has been used to write the Greek language since the late 9th or early 8th century BC. It was derived from the earlier Phoenician alphabet, and is the earliest known alphabetic script to systematically write vowels as wel ...
. It was derived from the
Phoenician letter
Yodh. Letters that arose from this letter include the
Latin
Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...
I and
J, the
Cyrillic
The Cyrillic script ( ) is a writing system used for various languages across Eurasia. It is the designated national script in various Slavic, Turkic, Mongolic, Uralic, Caucasian and Iranic-speaking countries in Southeastern Europe, Ea ...
І (І, і),
Yi (Ї, ї), and
Je (Ј, ј), and
iotated letters (e.g.
Yu (Ю, ю)). In the system of
Greek numerals
Greek numerals, also known as Ionic, Ionian, Milesian, or Alexandrian numerals, is a numeral system, system of writing numbers using the letters of the Greek alphabet. In modern Greece, they are still used for ordinal number (linguistics), ordi ...
, iota has a value of 10.
Iota represents the
close front unrounded vowel . In early forms of ancient Greek, it occurred in both long and short versions, but this distinction was lost in
Koine Greek
Koine Greek (, ), also variously known as Hellenistic Greek, common Attic, the Alexandrian dialect, Biblical Greek, Septuagint Greek or New Testament Greek, was the koiné language, common supra-regional form of Greek language, Greek spoken and ...
.
Iota participated as the second element in
falling diphthongs, with both long and short vowels as the first element. Where the first element was long, the iota was lost in pronunciation at an early date, and was written in
polytonic orthography
Greek orthography has used a variety of diacritics starting in the Hellenistic period. The more complex polytonic orthography (), which includes five diacritics, notates Ancient Greek phonology. The simpler monotonic orthography (), introduce ...
as
iota subscript, in other words as a very small ι under the main vowel. Examples include ᾼ ᾳ ῌ ῃ ῼ ῳ. The former diphthongs became
digraphs for simple vowels in
Koine Greek
Koine Greek (, ), also variously known as Hellenistic Greek, common Attic, the Alexandrian dialect, Biblical Greek, Septuagint Greek or New Testament Greek, was the koiné language, common supra-regional form of Greek language, Greek spoken and ...
.
[see Koine Greek phonology]
The word is used in a common English phrase, "not one iota", meaning "not the slightest amount". This refers to iota, the smallest letter, or possibly
yodh, י, the smallest letter in the Hebrew alphabet. The English word ''
jot'' derives from iota. The German, Polish, Portuguese, and Spanish name for the letter J (''
Jot'' / ''
jota'') is derived from iota.
Symbol
* In some
programming language
A programming language is a system of notation for writing computer programs.
Programming languages are described in terms of their Syntax (programming languages), syntax (form) and semantics (computer science), semantics (meaning), usually def ...
s (e.g.,
A+,
APL,
C++,
Go), iota (either as the lowercase symbol
⍳ or the identifier
iota) is used to represent and generate an array of consecutive integers. For example, in APL
⍳4 gives
1 2 3 4.
* The lowercase iota symbol is sometimes used to write the
imaginary unit
The imaginary unit or unit imaginary number () is a mathematical constant that is a solution to the quadratic equation Although there is no real number with this property, can be used to extend the real numbers to what are called complex num ...
, but more often Roman
i or
j is used.
* In
mathematics
Mathematics is a field of study that discovers and organizes methods, Mathematical theory, theories and theorems that are developed and Mathematical proof, proved for the needs of empirical sciences and mathematics itself. There are many ar ...
, the
inclusion map of one space into another is sometimes denoted by the lowercase iota.
* In
logic
Logic is the study of correct reasoning. It includes both formal and informal logic. Formal logic is the study of deductively valid inferences or logical truths. It examines how conclusions follow from premises based on the structure o ...
, the lowercase iota denotes the
definite descriptor.
* The lowercase iota symbol has Unicode code point U+03B9 and the uppercase U+0399.
Unicode
For accented Greek characters, see
Greek diacritics: Computer encoding.
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See also
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Hurricane Iota
References
{{Reflist
Greek letters
Vowel letters