Collins Concise English Dictionary © HarperCollins Publishers::

a, A // n ( pl a's, A's, 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 Zfrom start to finish, thoroughly and in detail
a /ə; (stressed or emphatic) / determiner (indefinite article; used before an initial consonant)
Compare an1
  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 noun or determiner of quantity: a cupful, a dozen eggs, a great many, to read a lot
  3. preceded by once, twice, several times, etc: each or every; per: once a day, fifty pence a pound
  4. a certain; one: to change policy at a stroke, a Mr Jones called
  5. (preceded by not) any at all: not a hope

See the1



A symbol for
  1. 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
  2. the major or minor key having this note as its tonic
  3. a human blood type of the ABO group, containing the A antigen
  4. (in Britain) a major arterial road
  5. ampere(s)
  6. absolute (temperature)
  7. area
  8. (in combination) atomic: an A-bomb, an A-plant
  9. a person whose job is in top management, or who holds a senior administrative or professional position
  10. (as modifier): an A worker
    See also occupation groupings



Å symbol for
  1. angstrom unit



'a' also found in these entries:
In the English description:

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