A1 (also a)
n noun (plural As or A’s)
1 the first letter of the alphabet.
2 denoting the first, best, or most important in a set.
3 Music the sixth note of the diatonic scale of C major, having a standard frequency of 440 Hz.
4 the human blood type (in the ABO system) containing the A antigen and lacking the B.
from A to B from one’s starting point to one’s destination.
from A to Z over the entire range.
1 (in card games) ace.
2 (in showing goals or points conceded) against.
4 (Å) ångström(s).
6 (in names of sports clubs) Athletic.
7 attack (in designations of US aircraft types): an A-10.
8 Austria (international vehicle registration).
a1 (an before a vowel sound)
1 used when mentioning someone or something for the first time; the indefinite article. Øone single: a hundred. Øused when mentioning someone unfamiliar: a Mr Smith telephoned. Øsomeone like (the name specified).
2 in, to, or for each; per: petrol prices rose by 3p a litre.
Middle English: weak form of Old English an ‘one’.
On the question of using a or an before words beginning with h, see usage at an.
1 (in travel timetables) arrives.
2 atto- (10-18).
3 British (with reference to sporting fixtures) away.
4 (used before a date) before. [from Latin ante.]
n symbol (a) Physics acceleration.
1 of: anew.
2 utterly: abash.
unstressed form of of (sense 1); Anglo-Norman French a-, from Latin ex (sense 2).
n suffix forming:
1 ancient or Latinized modern names of animals and plants: primula.
2 names of oxides: baryta.
3 geographical names: Africa.
4 ancient or Latinized modern feminine forenames: Lydia.
5 nouns from Italian, Portuguese, and Spanish: stanza.
representing a Greek, Latin, or Romance feminine singular
n suffix forming plural nouns:
1 from Greek or Latin neuter plurals corresponding to a singular in -um or -on (such as addenda, phenomena).
2 in names (often from modern Latin) of zoological groups: Insectivora.
n suffix informal
1 of: coupla.
2 have: mighta.
3 to: oughta.
n adjective informal excellent.
n noun a standard European size of paper, 420 × 297 mm.
n noun a standard European size of paper, 297 × 210 mm.
n noun a standard European size of paper, 210 × 148 mm.