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Definition of A in English :

Define A in English

A meaning in English

Meaning of A in English

Pronunciation of A in English

A pronunciation in English

Pronounce A in English

A

see synonyms of a

Noun

1. a, angstrom, angstrom unit

a metric unit of length equal to one ten billionth of a meter (or 0.0001 micron); used to specify wavelengths of electromagnetic radiation

2. a, antiophthalmic factor, axerophthol, vitamin a

any of several fat-soluble vitamins essential for normal vision; prevents night blindness or inflammation or dryness of the eyes

3. a, deoxyadenosine monophosphate

one of the four nucleotides used in building DNA; all four nucleotides have a common phosphate group and a sugar (ribose)

4. a, adenine

(biochemistry) purine base found in DNA and RNA; pairs with thymine in DNA and with uracil in RNA

5. a, amp, ampere

the basic unit of electric current adopted under the Systeme International d'Unites

Example Sentences:
'a typical household circuit carries 15 to 50 amps'

6. a

the 1st letter of the Roman alphabet

7. a, group a, type a

the blood group whose red cells carry the A antigen

WordNet Lexical Database for English. Princeton University. 2010.

A

see synonyms of a
nounWord forms: plural a's, A's or As
1. 
the first letter and first vowel of the modern English alphabet
2. 
any of several speech sounds represented by this letter, in English as in take, bag, calm, shortage, or cobra
3. Also called: alpha
the first in a series, esp the highest grade or mark, as in an examination
4.  from A to Z
determiner (indefinite article; used before an initial consonant)
1. 
used preceding a singular countable noun, if the noun is not previously specified or known
a dog
a terrible disappointment
2. 
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
3. 
used preceding a noun or determiner of quantity
a cupful
a dozen eggs
a great many
to read a lot
4. 
used preceding a noun indicating a concrete or abstract thing capable of being divided
half a loaf
a quarter of a minute
5. (preceded by once, twice, several times, etc)
each or every; per
once a day
fifty pence a pound
6. 
a certain; one
to change policy at a stroke
a Mr Jones called
7. (preceded by not)
any at all
not a hope
verb
an informal or dialect word for have
they'd a said if they'd known
preposition
(usually linked to the preceding noun) an informal form of of
sorta sad
a kinda waste
symbol for
1. 
acceleration
2. 
are(s) (metric measure of land)
3. 
atto-
4. chess algebraic notation
symbol for
1. music
a. 
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
b. 
a key, string, or pipe producing this note
c. 
the major or minor key having this note as its tonic
2. 
a human blood type of the ABO group, containing the A antigen
3. 
(in Britain) a major arterial road
the A3 runs from London to Portsmouth
4. (formerly, in Britain)
a. 
a film certified for viewing by anyone, but which contains material that some parents may not wish their children to see
b. 
(as modifier)
an A film
5. 
mass number
6. 
the number 10 in hexadecimal notation
7. cards
ace
8. chemistry
argon (now superseded by Ar)
9. 
ampere(s)
10. Also: at
ampere-turn
11. 
absolute (temperature)
12. 
(in circuit diagrams) ammeter
13. 
area
14. (in combination)
atomic
an A-bomb
an A-plant
15. chemistry
affinity
16. biochemistry
adenine
17. logic
a universal affirmative categorical proposition, such as all men are mortal: often symbolized as SaP
Compare E, I2, O1
18. 
a. 
a person whose job is in top management, or who holds a senior administrative or professional position
b. 
(as modifier)
an A worker
See also occupation groupings
abbreviation for
19. 
Austria (international car registration)
symbol for
angstrom unit
abbreviation for
1. 
acre(s) or acreage
2. 
America(n)
3. 
answer
determiner
Scottish variants of all

Collins English Dictionary. Copyright © HarperCollins Publishers

A

see synonyms of a
noun
1. 
a blood type
see also ABO system
2.  US, Education
a grade indicating excellence
an A in history
3.  Music
a. 
the sixth tone or note in the ascending scale of C major
b. 
a key, string, etc. producing this tone
c. 
the scale having this tone as the keynote
adjective
4. 
first-class; A 1
see also A one
1.  Physics
absolute
2. 
adenine
3. 
America(n)
4. 
ampere
5. 
analog
6. 
angstrom
: also Å
7. 
anode
8. 
answer
9. 
April
10.  Chemistry; Archaic
argon
11.  Baseball and Basketball and Hockey
assist(s)
12. 
attendance
13. 
August
nounWord forms: plural A's (eɪz ; āz) or a's
1. 
the first letter of the English alphabet: from the Greek alpha, a borrowing from the Phoenician
2. 
any of the speech sounds that this letter represents, as, in English, the vowel ( (æ) ; a) ) of hat, ( (ɑ) ; ä) ) of father, ( (eɪ) ; ā) ) of bake, or ( (ɔ) ; ô) ) of call
3. 
a type or impression for a or A
4. 
the first in a sequence or group
5. 
an object shaped like A
adjective
6. 
of a or A
7. 
first in a sequence or group
8. 
shaped like A
adjective, indefinite article
1. 
one; one sort of
we planted a tree
2. 
each; any one [a gun is dangerous]
a connotes a thing not previously noted or recognized, in contrast with the, which connotes a thing previously noted or recognized
preposition
3. 
to each; in each; for each; per
once a day
adjective
Scottish
all
1. 
about
2. 
absent
3.  Physics
acceleration
4. 
active
5. 
adjective
6. 
adult
7. 
alto
8. 
anonymous
9. 
answer
10. 
are (unit of area)
11. 
atto-

Webster’s New World College Dictionary, 4th Edition. Copyright © 2010 by Houghton Mifflin Harcourt. All rights reserved.

A

see synonyms of a
n. pl. a's or A's also as or As
1. The first letter of the modern English alphabet.
2. Any of the speech sounds represented by the letter a.
3. The first in a series.
4. Something shaped like the letter A.
5. A The best or highest in quality or rank: grade A milk.
6. Music
a. The sixth tone in the scale of C major or the first tone in the relative minor scale.
b. A key or scale in which A is the tonic.
c. A written or printed note representing this tone.
d. A string, key, or pipe tuned to the pitch of this tone.
7. A One of the four major blood groups in the ABO system. Individuals with this blood group have the A antigen on the surface of their red blood cells, and the anti-B antibody in their blood serum.
pref.
Without; not: amoral.
indef.art.
1. Used before nouns and noun phrases that denote a single but unspecified person or thing: a region; a person.
2. Used before terms that denote number, amount, quantity, or degree: only a few of the voters; a bit more rest; a little excited.
3.
a. Used before a proper name to denote a type or a member of a class: the wisdom of a Socrates.
b. Used before a mass noun to indicate a single type or example: a dry wine.
4. The same: birds of a feather.
5. Any: not a drop to drink.
pref.
1. On; in: abed.
2. In the act of: aborning.
3. In the direction of: astern.
4. In a specified state or condition: abuzz.
prep.
In every; to each; per: once a month; one dollar a pound.
aux.v.
Informal
Have: He'd a come if he could.
abbr.
1. acceleration
2. are (measurement)
abbr.
1. acre
2. adjective
3. Latin anno (in the year)
4. Latin annus (year)
5. anode
6. Latin ante (before)
7. anterior
abbr.
1. accusative
2. Games ace
3. across
4. adenine
5. alto
6. ampere
7. or Å angstrom
8. answer
9. area
10. Sports assist

The American Heritage ® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

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