E is the fifth letter of the Latin alphabet.
E or e may also refer to:
Commerce and transportation
* €, the symbol for the
euro
The euro ( symbol: €; code: EUR) is the official currency of 19 out of the member states of the European Union (EU). This group of states is known as the eurozone or, officially, the euro area, and includes about 340 million citizens . ...
, the European Union's standard currency unit
* ℮, the
estimated sign, an EU symbol indicating that the weight or volume of pre-packaged goods is within specific allowable tolerances
* E, the country identifier for
vehicle registration plates of Spain
Vehicle registration plates are the mandatory number plates used to display the registration mark of a vehicle, and have existed in Spain since 1900. Most motor vehicles which are used on public roads are required by law to display them. The gov ...
* E, a Polish electric locomotive in
PKP classification system
PKP classification system (Polish locomotive designation) is a system of assigning letters and numbers to series and individual locomotives used by the PKP - Polish national railroad operator.
The system was introduced for the steam stock by the ...
* E or
Eni
Eni S.p.A. () is an Italian multinational energy company headquartered in Rome. Considered one of the seven "supermajor" oil companies in the world, it has operations in 69 countries with a market capitalization of US$54.08 billion, as of 11 Ap ...
, an Italian oil and gas company
* E-Mark, an approval mark for automotive products in Europe under the
World Forum for Harmonization of Vehicle Regulations
*
E (Los Angeles Railway)
E refers to two streetcar routes in Los Angeles, California which were operated by the Los Angeles Railway. The first incarnation was in service from 1920 to 1932 when it was redesignated as route 5. The second existed between 1920 and 1946, tho ...
*
E (New York City Subway service)
The E Eighth Avenue Local is a rapid transit service in the B Division of the New York City Subway. Its route emblem, or "bullet", is blue since it uses the IND Eighth Avenue Line in Manhattan.
The E operates at all times between Jamaica Cen ...
, a Subway service in New York
*
E Line (Los Angeles Metro)
The E Line (formerly the Expo Line from 2012–2019) is a light rail line that runs between Downtown Los Angeles and Santa Monica. It is one of the seven lines in the Metro Rail system, and is operated by the Los Angeles County Metropolitan ...
*
Line E of the Buenos Aires Subte
Medicine and genetics
*
E number
E numbers ("E" stands for "Europe") are codes for substances used as food additives, including those found naturally in many foods such as vitamin C, for use within the European Union (EU) and European Free Trade Association (EFTA). Commonly ...
, a number code for a food additive, an EU labelling requirement
*
Haplogroup E (mtDNA)
In human mitochondrial genetics, haplogroup E is a human mitochondrial DNA (mtDNA) haplogroup typical for the Malay Archipelago. It is a subgroup of haplogroup M9.
Origin
Two contrasting proposals have been made for the location and time of th ...
, a human mitochondrial DNA (mtDNA) haplogroup
*
Haplogroup E (Y-DNA)
Haplogroup E-M96 is a human Y-chromosome DNA haplogroup. It is one of the two main branches of the older and ancestral haplogroup DE, the other main branch being Haplogroup D (Y-DNA), haplogroup D. The E-M96 clade is divided into two main clades, ...
, a Y-chromosomal DNA (Y-DNA) haplogroup
* E or
glutamic acid
Glutamic acid (symbol Glu or E; the ionic form is known as glutamate) is an α-amino acid that is used by almost all living beings in the biosynthesis of proteins. It is a non-essential nutrient for humans, meaning that the human body can synt ...
, an amino acid, glutamate
* ''E. coli'' or ''
Escherichia coli
''Escherichia coli'' (),Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. also known as ''E. coli'' (), is a Gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus ''Escher ...
'', a bacterium commonly found in the lower intestine; some are pathogenic, others are not
* ''E. coli'' or ''
Entamoeba coli
''Entamoeba coli'' is a non-pathogenic species of ''Entamoeba'' that frequently exists as a commensal parasite in the human gastrointestinal tract. ''E. coli'' (not to be confused with the bacterium ''Escherichia coli'') is important in medicine ...
'', a non-pathogenic parasite frequently found in the human intestine
* Vitamin E or
Tocopherol, a class of chemical compounds
* The symbol for the hormone
epinephrine
Adrenaline, also known as epinephrine, is a hormone and medication which is involved in regulating visceral functions (e.g., respiration). It appears as a white microcrystalline granule. Adrenaline is normally produced by the adrenal glands and ...
* E, a common abbreviation for 'Ecstasy' (a familiar name for the psychoactive recreational drug
MDMA
3,4-Methylenedioxymethamphetamine (MDMA), commonly seen in Tablet (pharmacy), tablet form (ecstasy) and crystal form (molly or mandy), is a potent empathogen–entactogen with stimulant properties primarily used for Recreational dru ...
)
*
Ethambutol
*
Estradiol (medication), particularly in transgender contexts
Physics and engineering
* e (or e
−) or
electron
The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family,
and are generally thought to be elementary particles because they have no kn ...
, a fundamental subatomic particle
* e or
elementary charge
The elementary charge, usually denoted by is the electric charge carried by a single proton or, equivalently, the magnitude of the negative electric charge carried by a single electron, which has charge −1 . This elementary charge is a fundame ...
, the absolute value of the electric charge carried by a single electron.
* e or
coefficient of restitution
The coefficient of restitution (COR, also denoted by ''e''), is the ratio of the final to initial relative speed between two objects after they collide. It normally ranges from 0 to 1 where 1 would be a perfectly elastic collision. A perfectl ...
(COR), a measure of the elasticity of a collision in mechanics
* E, the symbol for energy in equations concerning
mass-energy equivalence
* E or
Young's modulus
Young's modulus E, the Young modulus, or the modulus of elasticity in tension or compression (i.e., negative tension), is a mechanical property that measures the tensile or compressive stiffness of a solid material when the force is applied leng ...
, a measure of stiffness in solid mechanics
* E or
exa-
A metric prefix is a unit prefix that precedes a basic unit of measure to indicate a multiple or submultiple of the unit. All metric prefixes used today are decadic. Each prefix has a unique symbol that is prepended to any unit symbol. The pre ...
, the SI prefix for 10
18
*
E-layer or the Kennelly-Heaviside layer, part of the ionosphere
* E, the symbol for an
electric field
An electric field (sometimes E-field) is the physical field that surrounds electrically charged particles and exerts force on all other charged particles in the field, either attracting or repelling them. It also refers to the physical field fo ...
* e or
orbital eccentricity
In astrodynamics, the orbital eccentricity of an astronomical object is a dimensionless parameter that determines the amount by which its orbit around another body deviates from a perfect circle. A value of 0 is a circular orbit, values betwee ...
, a measure of how much a conic section deviates from a circle
* E or Equal Energy spectrum, a definition of
white
White is the lightest color and is achromatic (having no hue). It is the color of objects such as snow, chalk, and milk, and is the opposite of black. White objects fully reflect and scatter all the visible wavelengths of light. White on ...
in colour printing
* E, the
electrode potential
In electrochemistry, electrode potential is the electromotive force of a galvanic cell built from a standard reference electrode and another electrode to be characterized. By convention, the reference electrode is the standard hydrogen electrode (S ...
, the electromotive force of a cell built of two electrodes
** E° or
, the
standard electrode potential
Mathematics and logic
* , the mathematical constant also known as Euler's number and Napier's constant, a transcendental number and the base of natural logarithms, approximately equal to 2.718
*
E notation
Scientific notation is a way of expressing numbers that are too large or too small (usually would result in a long string of digits) to be conveniently written in decimal form. It may be referred to as scientific form or standard index form, o ...
, or scientific notation, a way of writing very large and very small numbers such as 5E7
* ∃ (a backwards E; U+2203) or
existential quantification
In predicate logic, an existential quantification is a type of quantifier, a logical constant which is interpreted as "there exists", "there is at least one", or "for some". It is usually denoted by the logical operator symbol ∃, which, whe ...
, the symbol for "there exists...", in predicate logic; ∃! meaning "there exists only one" (or "there exists exactly one") - see
Uniqueness quantification
* E, 14 in
hexadecimal
In mathematics and computing, the hexadecimal (also base-16 or simply hex) numeral system is a positional numeral system that represents numbers using a radix (base) of 16. Unlike the decimal system representing numbers using 10 symbols, hexa ...
and other positional numeral systems of a base of 15 or higher
*