a

[ uh; when stressed ey ]

indefinite article

not any particular or certain one of a class or group: a man; a chemical; a house.
a certain; a particular: one at a time; two of a kind; A Miss Johnson called.

another; one typically resembling: a Cicero in eloquence; a Jonah.
one (used before plural nouns that are preceded by a quantifier singular in form): a hundred men (compare hundreds of men); a dozen times (compare dozens of times).
indefinitely or nonspecifically (used with adjectives expressing number): a great many years; a few stars.
one (used before a noun expressing quantity): a yard of ribbon; a score of times.
any; a single: not a one.

Origin of a

First recorded in 1200–50; Middle English; originally preconsonantal phonetic variant of an¹

Grammar notes for a

In both spoken and written English the choice of a1 or an¹ is determined by the initial sound of the word that follows. Before a consonant sound, a is used; before a vowel sound, an : a book, a rose; an apple, an opera. Problems arise occasionally when the following word begins with a vowel letter but actually starts with a consonant sound, or vice versa. Some words beginning with the vowel letter u and all words beginning with the vowel letters eu are pronounced with a beginning consonant sound, as if the first letter were y : a union; a European. Some other spellings that begin with a vowel letter may also stand for an initial consonant sound: a ewe; a ewer. The words one and once and all compounds of which they are the first element begin with a w sound: a one-room apartment; a once-famous actor.
The names of the consonant letters f, h, l, m, n, r, s, and x are pronounced with a beginning vowel sound. When these letters are used as words or to form words, they are preceded by an : to rent an L-shaped studio; to fly an SST. The names of the vowel letter u and the semivowel letters w and y are pronounced with a beginning consonant sound. When used as words, they are preceded by a : a U-turn; The plumber installed a Y in the line.
In some words beginning with the letter h, the h is not pronounced; the words actually begin with a vowel sound: an hour; an honor. When the h is strongly pronounced, as in a stressed syllable at the beginning of a word, it is preceded by a : a history of the Sioux; a hero sandwich. (In former times an was used before strongly pronounced h in a stressed first syllable: an hundred. ) Such adjectives as historic, historical, heroic, and habitual, which begin with an unstressed syllable and often with a silent or weakly pronounced h, are commonly preceded by an, especially in British English. But the use of a rather than an is widespread in both speech and writing: a historical novel; a habitual criminal. Hotel and unique are occasionally preceded by an, but this use is increasingly old-fashioned. Although in some dialects an has yielded to a in all cases, edited writing reflects usage as described above.

Words Nearby a

Other definitions for a (2 of 28)

a²

[ uh; when stressed ey ]

preposition

each; every; per: ten cents a sheet; three times a day.

Origin of a

Originally Middle English a, preconsonantal variant of on (see a-¹); confused with a¹

Other definitions for a (3 of 28)

a³

[ uh ]

preposition

Informal. a reduced, unstressed form of of (often written as part of a single, unhyphenated word): cloth a gold; time a day; kinda; sorta.

Origin of a

Middle English; unstressed preconsonantal variant of of¹

Other definitions for a (4 of 28)

a⁴

[ uh ]

auxiliary verbInformal.

a reduced, unstressed form of auxiliary have following some modals, as might, should, could, would, and must (usually written as part of a single, unhyphenated word): We shoulda gone.

Origin of a

⁴

First recorded in 1300–50; Middle English; a phonetic variant of have

Compare of².

Other definitions for a (5 of 28)

a⁵

[ uh, a, ah ]

pronounBritish Dialect.

he¹.
she.

Origin of a

⁵

First recorded in 1200–50; Middle English a, ha

Other definitions for a (6 of 28)

a⁶

abbreviationMeasurements.

are; ares.

Other definitions for a' (7 of 28)

or a

[ ah, aw ]

adjectiveScots

all: for a' that.

Other definitions for A (8 of 28)

A¹

or a

[ ey ]

noun,plural A's or As, a's or as.

the first letter of the English alphabet, a vowel.
any spoken sound represented by the letter A or a, as in bake, hat, father, or small.

something having the shape of an A.
a written or printed representation of the letter A or a.
a device, as a printer's type, for reproducing the letter A or a.

Other definitions for A (9 of 28)

A²

abbreviation

Electricity. ampere; amperes.
Physics. angstrom; angstroms.

answer.
British. arterial (used with a road number to designate a major highway): Take the A525 to Ruthin.

Other definitions for A (10 of 28)

A³

Symbol.

the first in order or in a series.
Sometimes a .
- (in some grading systems) a grade or mark, as in school or college, indicating the quality of a student's work as excellent or superior.
- (in some school systems) a symbol designating the first semester of a school year.

Music.
- the sixth tone in the scale of C major or the first tone in the relative minor scale, A minor.
- a string, key, or pipe tuned to this tone.
- a written or printed note representing this tone.
- (in the fixed system of solmization) the sixth tone of the scale of C major, called la.
- the tonality having A as the tonic note.
Physiology. a major blood group, usually enabling a person whose blood is of this type to donate blood to persons of group A or AB and to receive blood from persons of O or A.: Compare ABO system.
Sometimes a . the medieval Roman numeral for 50 or 500.: Compare Roman numerals.
Chemistry. (formerly) argon.
Chemistry, Physics. mass number.
Biochemistry.
- adenine.
- alanine
Also a .Logic. universal affirmative.
British. a designation for a motion picture recommended as suitable for adults.: Compare AA² (def. 5), U⁵ (def. 6), X³ (def. 9).
a proportional shoe width size, narrower than B and wider than AA.
a proportional brassiere cup size, smaller than B and larger than AA.
a quality rating for a corporate or municipal bond, lower than AA and higher than BBB.

Other definitions for a- (11 of 28)

a-¹

a reduced form of the Old English preposition on, meaning “on,” “in,” “into,” “to,” “toward,” preserved before a noun in a prepositional phrase, forming a predicate adjective or an adverbial element (afoot; abed; ashore; aside; away), or before an adjective (afar; aloud; alow), as a moribund prefix with a verb (acknowledge), and in archaic and dialectal use before a present participle in -ing (set the bells aringing); and added to a verb stem with the force of a present participle (ablaze; agape; aglow; astride; and originally, awry).

Origin of a-

¹¹

Middle English, late Old English; cf. a², nowadays

Other definitions for a- (12 of 28)

a-²

a reduced form of the Old English preposition of: akin; afresh; anew.

Origin of a-

¹²

Middle English; see a³

Other definitions for a- (13 of 28)

a-³

an old point-action prefix, not referring to an act as a whole, but only to the beginning or end: She arose (rose up). They abided by their beliefs (remained faithful to the end).

Origin of a-

¹³

Middle English; Old English a- (unstressed), ǣ-, ā-, ō- (stressed; see abb, woof¹, oakum), rarely or- (see ordeal), ultimately from unattested Germanic uz- from unstressed Indo-European uss-, from ud-s (these latter two also unattested), akin to out; in some cases confused with a-⁴, as in abridge

Other definitions for a- (14 of 28)

a-⁴

variant of ab- before p and v: aperient; avert.

Origin of a-

¹⁴

Middle English <Latin ā-, a- (variant of ab-ab-); in some words <French a-<Latin ab-, as in abridge

Other definitions for a- (15 of 28)

a-⁵

variant of ad-, used: (1) before sc, sp, st (ascend) and (2) in words of French derivation (often with the sense of increase, addition): amass.

Origin of a-

¹⁵

Middle English, in some words <Middle French a-<Latin ad- prefix or ad preposition (see ad-), as in abut; in others <Latin a- (variant of ad-ad-), as in ascend

Other definitions for a- (16 of 28)

a-⁶

variant of an-¹ before a consonant, meaning “not,” “without”: amoral; atonal; achromatic.

Other definitions for A- (17 of 28)

A-

atomic (used in combination): A-bomb; A-plant.

Other definitions for -a (18 of 28)

-a¹

a plural ending of nouns borrowed from Greek and Latin: phenomena; criteria; data; errata; genera.

Other definitions for -a (19 of 28)

-a²

a feminine singular ending of nouns borrowed from Latin and Greek, also used in New Latin coinages to Latinize bases of any origin, and as a Latin substitute for the feminine ending -ē of Greek words: anabaena;cinchona;pachysandra.

Other definitions for -a (20 of 28)

-a³

an ending of personal names forming feminines from masculines: Georgia; Roberta.

Origin of -a

²⁰

From Latin feminine ending -a, as Claudia, feminine of Claudius; see -a²

Other definitions for -a (21 of 28)

-a⁴

a suffix designating the oxide of the chemical element denoted by the stem: alumina; ceria; thoria.

Origin of -a

²¹

Probably generalized from the -a of magnesia

Other definitions for Å (22 of 28)

Symbol, Physics.

angstrom.

Other definitions for a. (23 of 28)

a.¹

abbreviation

year.

Origin of a.

²³

<Latin annō, ablative of annus

Other definitions for a. (24 of 28)

a.²

abbreviation

before.

Origin of a.

²⁴

From the Latin word ante

Other definitions for a. (25 of 28)

a.³

abbreviation

about.
acre; acres.

active.
adjective.
alto.
ampere; amperes.
anonymous.
answer.
are; ares.
Baseball. assist; assists.

Other definitions for A. (26 of 28)

A.¹

abbreviation

year.

Origin of A.

²⁶

<Latin annō, ablative of annus

Other definitions for A. (27 of 28)

A.²

abbreviation

before.

Origin of A.

²⁷

From the Latin word ante

Other definitions for A. (28 of 28)

A.³

abbreviation

Absolute.
Academy.

acre; acres.
America.
American.
angstrom.
answer.
April.
Artillery.

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use a in a sentence

a timeline for election officials put together by the Department of Homeland Security showed that the process for expanding mail-in voting should have begun in April.
Vote by mail: Which states allow absentee voting | Kate Rabinowitz, Brittany Mayes | September 17, 2020 | Washington Post
a big question in public health law is how far an executive, such as a governor, can go without legislative approval.
Courts may reconsider temporary coronavirus restrictions as pandemic drags on | Anne Gearan, Karin Brulliard | September 16, 2020 | Washington Post
a total of about 26 million doses of vaccine B would be available by the end of the year, most of them in December.
Top health official says states need about $6 billion from Congress to distribute coronavirus vaccine | Lena H. Sun | September 16, 2020 | Washington Post
a number of recent polls at the state level have measured both the presidential election and Senate races.
If voters are wary of stating support for Trump in polls, why does he outperform GOP Senate candidates? | Philip Bump | September 16, 2020 | Washington Post
a waiter touching a plate with a bare hand is indeed not ideal, which is why waiters are generally instructed to wear gloves.
Parsing Trump’s baffling, head-slapping comments on mask-wearing | Philip Bump | September 16, 2020 | Washington Post

ROME — What does it take for a Hollywood a-lister to get a private audience with Pope Francis?
Pope Francis Has the Pleasure of Meeting Angelina Jolie for a Few Seconds | Barbie Latza Nadeau | January 8, 2015 | THE DAILY BEAST
Yes, Byrd—dead four-and-a-half years now—was a Kleagle in the Ku Klux Klan.
Steve Scalise and the Right’s Ridiculous Racial Blame Game | Michael Tomasky | January 2, 2015 | THE DAILY BEAST
By the time it concluded with a sing-a-long of “XO,” Beyoncé had done the rare thing.
Bow Down, Bitches: How Beyoncé Turned an Elevator Brawl Into a Perfect Year | Kevin Fallon | December 31, 2014 | THE DAILY BEAST
In another year, stories about the strange new face of an a-list actress might draw chortles and cackles.
Renée Zellweger Got a New Face—and Everyone Had An Opinion About It | Kevin O’Keeffe | December 29, 2014 | THE DAILY BEAST
Because Duck Dynasty receives monster TV ratings and Robertson paid by a company (a&E) while making these public statements.
Butts, Brawls, and Bill Cosby: The Biggest Celebrity Scandals of 2014  | Kevin Fallon | December 27, 2014 | THE DAILY BEAST
Now-a-days it is the bankrupt who flouts, and his too confiding creditors who are jeered and laughed at.
Glances at Europe | Horace Greeley
He felt himself the meanest, vilest thing a-crawl upon this sinful earth, and she—dear God!
St. Martin's Summer | Rafael Sabatini
All that scientific bric-a-brac in the cupboard had far better be thrown away.
The Salvaging Of Civilisation | H. G. (Herbert George) Wells
Urinary sediments may be studied under three heads: a. Unorganized sediments.
A Manual of Clinical Diagnosis | James Campbell Todd
I knowed, a-course, that I could go kick up a fuss when Simpson stopped by his office on his trip back from Goldstone.
Alec Lloyd, Cowpuncher | Eleanor Gates

British Dictionary definitions for a (1 of 11)

a¹

/ (ə, stressed or emphatic eɪ) /

determiner(indefinite article; used before an initial consonant)

used preceding a singular countable noun, if the noun is not previously specified or known: a dog; a terrible disappointment
used preceding a proper noun to indicate that a person or thing has some of the qualities of the one named: a Romeo; a Shylock

used preceding a noun or determiner of quantity: a cupful; a dozen eggs; a great many; to read a lot
used preceding a noun indicating a concrete or abstract thing capable of being divided: half a loaf; a quarter of a minute
(preceded by once, twice, several times, etc) each or every; per: once a day; fifty pence a pound
a certain; one: to change policy at a stroke; a Mr Jones called
(preceded by not) any at all: not a hope

Compare an 1
See the 1

British Dictionary definitions for a (2 of 11)

a²

/ (ə) /

verb

an informal or dialect word for have they'd a said if they'd known

British Dictionary definitions for a (3 of 11)

a³

/ (ə) /

preposition

(usually linked to the preceding noun) an informal form of of sorta sad; a kinda waste

British Dictionary definitions for a (4 of 11)

a⁴

symbol for

acceleration
are(s) (metric measure of land)

atto-
chess See algebraic notation

British Dictionary definitions for a (5 of 11)

A

/ (eɪ) /

nounplural a's, A's or As

the first letter and first vowel of the modern English alphabet
any of several speech sounds represented by this letter, in English as in take, bag, calm, shortage, or cobra

Also called: alpha the first in a series, esp the highest grade or mark, as in an examination
from A to Z from start to finish, thoroughly and in detail

British Dictionary definitions for a' (6 of 11)

aa or aw

/ (ɔː) /

determiner

Scot variants of all

British Dictionary definitions for A (7 of 11)

symbol for

music
- a note having a frequency of 440 hertz (A above middle C) or this value multiplied or divided by any power of 2; the sixth note of the scale of C major
- a key, string, or pipe producing this note
- the major or minor key having this note as its tonic
a human blood type of the ABO group, containing the A antigen

(in Britain) a major arterial road: the A3 runs from London to Portsmouth
(formerly, in Britain)
- a film certified for viewing by anyone, but which contains material that some parents may not wish their children to see
- (as modifier): an A film
mass number
the number 10 in hexadecimal notation
cards ace
chem argon (now superseded by Ar)
ampere(s)
Also: at ampere-turn
absolute (temperature)
(in circuit diagrams) ammeter
area
(in combination) atomic: an A-bomb; an A-plant
chem affinity
biochem adenine
logic a universal affirmative categorical proposition, such as all men are mortal: often symbolized as SaP: Compare E, I 2, O 1
- a person whose job is in top management, or who holds a senior administrative or professional position
- (as modifier): an A worker See also occupation groupings

abbreviation for

Austria (international car registration)

Origin of A

⁷

from Latin a (ffirmo) I affirm

British Dictionary definitions for a- (8 of 11)

a-¹

prefix

not; without; opposite to: atonal; asocial

Origin of a-

⁸

from Greek a-, an- not, without

British Dictionary definitions for a- (9 of 11)

a-²

prefix

on; in; towards: afoot; abed; aground; aback
literary, or archaic (used before a present participle) in the act or process of: come a-running; go a-hunting

in the condition or state of: afloat; alive; asleep

British Dictionary definitions for Å (10 of 11)

symbol for

angstrom unit

British Dictionary definitions for A. (11 of 11)

abbreviation for

acre(s) or acreage
America(n)

answer

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for A (1 of 3)

Abbreviation of adenine, ampere, angstrom, area

Scientific definitions for a- (2 of 3)

A prefix meaning without or not when forming an adjective (such as amorphous, without form, or atypical, not typical), and absence of when forming a noun (such as arrhythmia, absence of rhythm). Before a vowel or h it becomes an- (as in anhydrous, anoxia).

Scientific definitions for Å (3 of 3)

Abbreviation of angstrom

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