In Spanish, a means to or towards.

In India, A is a movie rating, given to those intended to be seen only by adults.

In film:

In some sports, A is an abbreviation for Assists.

In radio,

A, or "side A," refers to the top or first side of a vinyl record.

The Oakland Athletics are often simply referred to as the "A's."

As a programming language, A may refer to:

A human blood type, also A+ and A-.

In French,

In Interlingua, a means at or to.

A whitish-blue class of stars in the Morgan-Keenan system in astronomy.

A (song), a song by the band Barenaked Ladies.

Vitamin A (also called retinol), an essential human nutrient.

As the first letter of a postal code,

relative atomic mass (A_r)

rotational constant (A)

In Christian theology, alpha is a metaphor for the beginning/creation of time and matter. It is sometimes translated to A.

adsorbed

A sometimes represents the set of all alphabetic characters within string patterns.

The anode, a component of a vacuum tube.

acceleration (a, upper-case for an initial/constant accleration value; lower case for an instantaneous acceleration variable)

area (A)

A (album), an album by progressive rock band Jethro Tull

A digit meaning ten in hexadecimal and other positional numeral systems with a radix of 11 or greater.

The semi-major axis of an orbit.

magnetic vector potential (A)

A (band), a British alternative rock band.

The universal quantifier in symbolic logic (symbol ∀ or <math>\forall</math> (an inverted letter A).

A is a brassiere cup size.

A is a security division ("Verified Protection") in the TCSEC.

A Band, an experimental group.

ampere (A) , the SI base unit of electric current

A is the first letter of the Latin alphabet. It can also refer to the following: In the sciences:

Helmholtz energy, A

A, an, the indefinite article in English.

Sometimes in blackboard bold represents the algebraic numbers (<math>\mathbb{A}</math> (U+1D538 in Unicode).

"A", a song by the band Cartel

nucleon number (A)

mass number (A)

"A" is a Kannada movie directed by Upendra.

A (Rating), in the CBFC system.

Bohr radius (a₀)

The center of a hexagonal face of the Brillouin zone of a hexagonal lattice, in physics.

"A" (song), Ayumi Hamasaki's 10th single

A (musical note), the sixth musical note.

Haplogroup A (Y-DNA), a Y-chromosomal DNA (Y-DNA) haplogroup.

A (kana), the Japanese kana あ and ア which may be used to represent Asia.

absorbance (A)

A+ programming language

A January 1 through 15 discovery, in the provisional designation of a comet (for example, C/1760 A1, the Great Comet of 1760) or asteroid (for example, (4099) 1988 AB₅).

specific surface area (a)

the NATO A band ranges below 0.25 GHz.

absorption coefficient (a)

A battery, a standard size of battery.

A Sharp (Axiom), properly known as "A#", an object-oriented functional programming language

A-0 programming language

Haplogroup A (mtDNA), a human mitochondrial DNA (mtDNA) haplogroup.

thermal diffusivity (a)

BASIC A+, a programming language

A#

activity (a)

pre-exponential factor (A)

A (Cass McCombs album), an album by Cass McCombs

ARITH-MATIC, an extension of the A-2 programming language

A (New York City Subway service), a service of the New York City Subway.

The symbol for the nitrogenous nucleic acid adenine, alanine and adenosine in biochemistry.

are, the deprecated symbol for the unit of surface area equal to 100 square metres

atto, the SI prefix meaning 10⁻¹⁸

year, from the Latin annum, especially in geology, archeology and astronomy; as prefixed with Mega (Ma) or Giga (Ga) to indicate periods of time.

A: is the conventional address of the first floppy disk drive in CP/M-based operating systems such as DOS.

In fiction, the letter worn by Hester Prynne marking her as an adulteress in the Nathaniel Hawthorne novel The Scarlet Letter was an A.

In poetry, A is the major work of influential twentieth century author Louis Zukofsky.

a is the Third person singular conjugation, Present tense of the verb avoir: «il a»="he has".

In Portuguese, it is either the feminine definite article or a preposition meaning "to", "toward".

In Greek, a- is a prefix (alpha privativum) meaning "not" or "devoid of," used in many borrowed words in English, German and Romance languages (for example, amoral, asexual, arhythmic).

In Esperanto as well as in Ido, -a is the adjectival/attributive ending; A is commonly an abbreviation meaning English (language).

In American Major League Baseball,

A can stand for Appearances or Assist.

In calendars, A is often an abbreviation for the months April and August.

In education, a grade of A typically represents the highest score that students can achieve. This is sometimes coupled with a plus/minus sign, as in A+ or A-, or a number, as in A1. It is occasionally a grade one level below A* (pronounced "A Star"). In Colombia, Finland, and New Zealand, A is the grade above a fail in a Pass ("Approve")/Fail test.

In finance, A is the U.S. ticker symbol for Agilent Technologies.

In games, the letter A is used to mark each of the Aces in a deck of playing cards.

In international licence plate codes, A stands for Austria.

In international paper sizes, A is a series of sizes with an aspect ratio of roughly 70% width to height, with A4 being an example popular size.

In photography, most SLR cameras use A to signify aperture priority mode, where the user sets the aperture and the camera determines the shutter speed.

In political theory, an A in a full circle is an anarchist symbol.

In Canada, A stands for Newfoundland and Labrador.

On the serial numbers of United States dollars, A identifies the Federal Reserve Bank of Boston.

As a timezone, A is the military designation for Coordinated Universal Time+1, also known as CET or Central European Time.

Topographically, A is used to describe an object shaped like the capital letter A, such as an A-frame.

A name intended for a Swedish child born in 1991.