1

a

play
noun, often capitalized, often attributive \ ˈā \

Definition of a

plural a's or as play \ˈāz\
1 a :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
5 a :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

Examples of a in a Sentence

  1. a word that begins with an a

  2. a word that begins with a

  3. a song in the key of A

  4. She got an A on the exam.

First Known Use of a

before 12th century

Other Alphabet Terms


2

a

play
indefinite article \ ə , (ˈ)ā , Canadian ˈa \

Definition of a

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
3 a used as a function word before a singular noun followed by a restrictive modifier
  • a man who was here yesterday
b :any
  • a man 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
4 used as a function word with nouns to form adverbial phrases of quantity, amount, or degree
  • felt a bit tired

a vs. an

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)


Origin and Etymology of a

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


3

a

play
preposition \ ə also (ˈ)ā \

Definition of a

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

a vs. an

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)


Origin and Etymology of a

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


4

a

play
verb \ ə , (ˌ)a \

Definition of a

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

Origin and Etymology of a

Middle English, contraction of have


5

a

play
preposition \ ə \

Definition of a

:of often attached to the preceding word
  • kinda
  • lotta

Origin and Etymology of a

Middle English, by contraction


6

a

abbreviation

Definition of a

1 absent
2 acceleration
3 acre
4 adult
5 alto
6 anode
7 answer
8 ante
9 anterior
10 are
11 area
12 atto-
13 author

1

a-

prefix \ ə \

Definition of a-

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

Origin and Etymology of a-

Middle English, from Old English


2

a-

prefix \ (ˈ)ā also (ˈ)a or (ˈ)ä \
variants: or an- \(ˈ)an\

Definition of a-

:not :without
  • asexual
a- before consonants other than h and sometimes even before h, an- before vowels and usually before h
  • achromatic
  • ahistorical
  • anastigmatic
  • anhydrous

Origin and Etymology of a-

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


-a-

combining form

Definition of -a-

:replacing carbon especially in a ring
  • aza-

Origin and Etymology of -a-

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


-a

noun suffix \ ə \

Definition of -a

:oxide
  • silica

Origin and Etymology of -a

New Latin, from -a (as in magnesia)


1

A

abbreviation

Definition of A

1 ace
2 adenine
3 ampere

2

A

symbol

Definition of A

argon

3

Å

abbreviation

Definition of Å

angstrom unit

A Defined for English Language Learners

noun

Definition of a for English Language Learners

  • : the first letter of the English alphabet

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

  • : a grade that is given to a student for doing excellent work


indefinite article

Definition of a for English Language Learners

  • —used before singular nouns when the person or thing is being mentioned for the first time

  • —used like one before number words like hundred, thousand, etc.

  • —used like one before number words like third, fortieth, etc.


A Defined for Kids

1

a

play
noun, often capitalized \ ˈā \

Definition of a for Students

plural a's or as \ˈāz\
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

2

a

play
indefinite article \ ə , ˈā \

Definition of a for Students

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 :1any 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 :2one 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 \

Definition of a- for Students

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

Medical Dictionary

a

abbreviation

medical Definition of a

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

play
noun \ ˈā \

medical Definition of A

: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

1 adenine
2 ampere

Å

symbol

medical Definition of Å

angstrom


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