a

noun, often capitalized, often attributive
\ ˈā How to pronounce a (audio) \
plural a's or as\ ˈāz How to pronounce a (audio) \

Definition of a

 (Entry 1 of 13)

1a : the 1st letter of the English alphabet
b : a graphic representation of this letter
c : a speech counterpart of orthographic a
2 : the sixth tone of a C-major scale
3 : a graphic device for reproducing the letter a
4 : one designated a especially as the first in order or class
5a : a grade rating a student's work as superior in quality
b : one graded or rated with an A
6 : something shaped like the letter A
7 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
\ ə, for emphasis (ˈ)ā How to pronounce a (audio) , Canadian ˈa How to pronounce a (audio) \

Definition of a (Entry 2 of 13)

1 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
2 : the same birds of a feather swords all of a length
3a used as a function word before a singular noun followed by a restrictive modifier a man who was here yesterday
b : any a person who is sick can't work
c used as a function word before a mass noun to denote a particular type or instance a bronze made in ancient times
d used as a function word before a proper noun representing an example or type the attractions of a Boston or a Cleveland
e 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
f 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
g used before the name of a day of the week to refer to one occurrence of it Christmas falls on a Tuesday this year.
h 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.
i 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
4 used as a function word with nouns to form adverbial phrases of quantity, amount, or degree felt a bit tired
\ ə also (ˈ)ā How to pronounce a (audio) \

Definition of a (Entry 3 of 13)

1 : in, to, or for each twice a week
2 chiefly dialectal : on, in, at
\ ə \

Definition of a (Entry 4 of 13)

: of often attached to the preceding word kindalotta

a

verb
\ ə, (ˌ)a How to pronounce a (audio) \

Definition of a (Entry 5 of 13)

archaic
: have I might a had husbands afore now— John Bunyan

Definition of a (Entry 6 of 13)

1 absent
2 acceleration
3 acre
4 adult
5 alto
6 chemistry amorphous usually used in combination a-Si
7 anode
8 answer
9 ante
10 anterior
11 are
12 area
13 atto-
14 author
\ ə \

Definition of a- (Entry 7 of 13)

1 : on : in : at abed
2 : in (such) a state or condition afire
3 : in (such) a manner aloud
4 : in the act or process of gone a-hunting atingle
\ (ˈ)ā also (ˈ)a or (ˈ)ä \
variants: or an- \ (ˈ)an \

Definition of a- (Entry 8 of 13)

: not : without asexual a- before consonants other than h and sometimes even before h, an- before vowels and usually before h achromaticahistoricalanastigmaticanhydrous

Definition of -a- (Entry 9 of 13)

: replacing carbon especially in a ring aza-
\ ə \

Definition of -a (Entry 10 of 13)

: oxide silica

Definition of A (Entry 11 of 13)

1 ace
2 adenine
3 ampere

A

symbol

Definition of A (Entry 12 of 13)

argon

Definition of Å (Entry 13 of 13)

angstrom

A vs. an: Usage Guide

Indefinite article

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)

Words Starting With a

Browse 22,515 words and phrases that start with the letter A, from aa to Azzazame.

Examples of a in a Sentence

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.

First Known Use of a

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

History and Etymology for a

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)

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Time Traveler for a

Time Traveler

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

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Dictionary Entries Near a

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a

a-

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Statistics for a

Last Updated

15 Apr 2022

Cite this Entry

“A.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/a. Accessed 21 May. 2022.

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More Definitions for a

a

noun, often capitalized
\ ˈā How to pronounce a (audio) \
plural a's or as\ ˈāz \

Kids Definition of a

 (Entry 1 of 3)

1 : the first letter of the English alphabet
2 : a grade that shows a student's work is excellent
3 : a musical note referred to by the letter A

a

indefinite article
\ ə How to pronounce a (audio) , ˈā \

Kids Definition of a (Entry 2 of 3)

1 : someone or something being mentioned for the first time There's a dog in the yard.
2 : the same two of a kind
3 : any entry 1 sense 1 It's hard for a person to understand.
4 : for or from each an apple a day The new theater charges ten dollars a person.
5 : one entry 2 sense 3 a dozen doughnuts a week This is a third the size of that.
Hint: A is used before words that do not begin with a vowel sound.

a-

prefix
\ ə \

Kids Definition of a-

1 : on : in : at abed
2 : in (such) a state, condition, or manner afire aloud
3 : in the act or process of gone a-hunting

a

abbreviation

Medical Definition of a

 (Entry 1 of 4)

1 about
2 absent
3 absolute
4 absorbency; absorbent
5 accommodation
6 acetum
7 acid; acidity
8 actin
9 active; activity
10 allergist; allergy
11 alpha
12 anode
13 answer
14 ante
15 anterior
16 aqua
17 area
18 artery
19 asymmetric; asymmetry

A

noun
\ ˈā How to pronounce A (audio) \

Medical Definition of A (Entry 2 of 4)

: 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

A

abbreviation

Medical Definition of A (Entry 3 of 4)

1 adenine
2 ampere

Å

symbol

Medical Definition of Å (Entry 4 of 4)

angstrom

More from Merriam-Webster on a

Nglish: Translation of a for Spanish Speakers

Britannica English: Translation of a for Arabic Speakers

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