a

1 of 13

noun

ˈā

plural a's or as ˈāz

often capitalized, often attributive

: the 1st letter of the English alphabet

: a graphic representation of this letter

: a speech counterpart of orthographic a

: the sixth tone of a C-major scale

: a graphic device for reproducing the letter a

: one designated a especially as the first in order or class

: a grade rating a student's work as superior in quality

: one graded or rated with an A

: something shaped like the letter A

capitalized : the one of the four ABO blood groups characterized by the presence of antigens designated by the letter A and by the presence of antibodies against the antigens present in the B blood group

2 of 13

indefinite article

ə,

for emphasis

(ˈ)ā

Canadian

ˈa

—used as a function word before singular nouns when the referent is unspecified

a man overboard

and before number collectives and some numbers

a dozen

: the same

birds of a feather

swords all of a length

—used as a function word before a singular noun followed by a restrictive modifier

a man who was here yesterday

: any

a person who is sick can't work

—used as a function word before a mass noun to denote a particular type or instance

a bronze made in ancient times

—used as a function word before a proper noun representing an example or type

the attractions of a Boston or a Cleveland

—used as a function word before a proper noun to indicate limited knowledge about the referent

a Mr. Smith called to inquire about the job

—used as a function word before a proper noun to distinguish the condition of the referent from a usual, former, or hypothetical condition

a triumphant Ms. Jones greeted her supporters

—used before the name of a day of the week to refer to one occurrence of it

Christmas falls on a Tuesday this year.

—used before the name of a person (such as a famous artist) when the name is being used to refer to something (such as a painting) created by that person

Her violin is a Stradivarius.

—used before a family name to show that someone is a member of that family

To be a Kennedy is to lead two lives …

Margaret Carlson

—used as a function word with nouns to form adverbial phrases of quantity, amount, or degree

felt a bit tired

A vs. an: Usage Guide

In speech and writing a is used before a consonant sound.

a door

a human

Before a vowel sound an is usual

an icicle

an honor

but especially in speech a is used occasionally, more often in some dialects than in others.

a apple

a hour

a obligation

Before a consonant sound represented by a vowel letter a is usual

a one

a union

but an also occurs though less frequently now than formerly.

an unique

such an one

Before unstressed or weakly stressed syllables with initial h both a and an are used in writing.

a historic

an historic

In the King James Version of the Old Testament and occasionally in writing and speech an is used before h in a stressed syllable.

an huntress

an hundred

children are an heritage of the Lord

Psalms 127:3 (King James Version)

3 of 13

preposition (1)

ə,

also

(ˈ)ā

: in, to, or for each

twice a week

chiefly dialectal : on, in, at

4 of 13

preposition (2)

informal

: of

There are a lot a stairs, but the view at the top is absolutely beautiful.

Auli'i Cravalho, quoted in The New York Times

—often attached to the preceding word

But I did kinda sorta secretly hope to one day be interviewed from Oprah Winfrey's yoga nook.

Jennifer SeniorThat's a whole lotta [=lot of] hypothesizin' without a whole lotta science.

Rebecca Watson

5 of 13

verb

ə,

(ˌ)a

archaic

: have

I might a had husbands afore now …

John Bunyan

Poor Sir William! never shall I forget how he looked whin my lady and he parted. I could a tould the reason, but I'd a cut my tongue out first.

Anne Newport Royall

6 of 13

abbreviation (1)

absent

acceleration

acre

adult

alto

chemistry amorphous

—usually used in combination

a-Si

anode

answer

ante

are

area

atto-

author

7 of 13

prefix (1)

: on : in : at

abed

: in (such) a state or condition

afire

: in (such) a manner

aloud

: in the act or process of

gone a-hunting

atingle

8 of 13

prefix (2)

(ˈ)ā,

also (ˈ)a,

or (ˈ)ä

variants or an-

(ˈ)an

: not : without

asexual

—a- before consonants other than h and sometimes even before h, an- before vowels and usually before h

achromaticahistoricalanastigmaticanhydrous

-a-

9 of 13

combining form

: replacing carbon especially in a ring

aza-

-a

10 of 13

noun suffix

: oxide

silica

alumina

magnesia

11 of 13

abbreviation (2)

ace

adenine

ampere

12 of 13

symbol

argon

13 of 13

abbreviation (3)

angstrom

Example Sentences

Noun a word that begins with an a a word that begins with a a song in the key of A She got an A on the exam.

Word History

Etymology

Indefinite article

Middle English, from Old English ān one — more at one

Preposition (1)

Middle English, from Old English a-, an, on

Preposition (2)

Middle English, by contraction

Verb

Middle English, contraction of have

Prefix (1)

Middle English, from Old English

Prefix (2)

Latin & Greek; Latin, from Greek — more at un-

Combining form

perhaps from -a- in ring compounds such as thiazole (in which -a- is the initial of azole)

Noun suffix

New Latin, from -a (as in magnesia)

First Known Use

Noun

before the 12th century, in the meaning defined at sense 1a

Indefinite Article

before the 12th century, in the meaning defined at sense 1

Preposition (1)

before the 12th century, in the meaning defined at sense 2

Preposition (2)

15th century, in the meaning defined above

Verb

14th century, in the meaning defined above

Time Traveler

The first known use of a was before the 12th century

See more words from the same century

Articles Related to a

Every Letter Is Silent, Sometimes

When each letter can be seen but not heard

7 Uncommonly Doubled Letters

For word games and other shenanigans

'A' and 'An' and the Patterns of Their...

Which gets used where?

Cite this Entry

Style

“A.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/a. Accessed 7 Dec. 2022.

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Kids Definition

1 of 5 noun

ˈā

plural a's or as

often capitalized

: the first letter of the English alphabet

: a musical note referred to by the letter A : the sixth tone of a C-major scale

: a grade rating a student's work as superior

2 of 5 indefinite article

(ˈ)ā

: someone or something unspecified

a man in the street

a dozen

: the same : one

two of a kind

birds of a feather

: of whatever kind : any

a person who is sick can't work well

—used in all senses before words beginning with a consonant sound compare an

3 of 5 preposition

(ˈ)ā

: in each : to each : for each

twice a week

one a piece

4 of 5 prefix

: on : in : at

abed

: in a specified state or condition

afire

: in a specified manner

aloud

: in the act or process of

gone a-hunting

5 of 5 prefix

(ˈ)ā

variants or an-

(ˈ)an

: not : without

asexual

—a- before consonants other than h and sometimes before h, an- before vowels and usually before h

anhydrate

Medical Definition

1 of 4 abbreviation

about

absent

absolute

absorbency; absorbent

accommodation

acetum

acid; acidity

actin

active; activity

allergist; allergy

alpha

anode

answer

ante

aqua

area

artery

asymmetric; asymmetry

2 of 4 noun

ˈā

: the one of the four ABO blood groups characterized by the presence of antigens designated by the letter A and by the presence of antibodies against the antigens present in the B blood group

3 of 4 abbreviation

adenine

ampere

4 of 4 symbol

angstrom