/ eɪ; NAmE / noun , symbol , abbreviation
■ noun (also a ) ( pl. As , A's , a's / eɪz; NAmE /)
1.
[ C , U ] the first letter of the English alphabet :
'Apple' begins with (an) A / 'A'.
2.
A [ C , U ] ( music ) the 6th note in the scale of C major
3.
[ C , U ] the highest mark / grade that a student can get for a piece of work or course of study :
She got (an) A in / for Biology.
He had straight A's (= nothing but A's) all through high school.
4.
A [ U ] used to represent the first of two or more possibilities :
Shall we go for plan A or plan B?
5.
A [ U ] used to represent a person, for example in an imagined situation or to hide their identity :
Assume A knows B is guilty.
—see also A-frame , A level , A-road
•
IDIOMS
- from A to B
- from A to Z
■ symbol
1.
used in Britain before a number to refer to a particular important road :
the A34 to Newbury
2.
used (but not in the US) before numbers which show standard metric sizes of paper :
a sheet of A4 paper (= 297×210mm)
A3 (= 420×297mm)
A5 (= 210×148mm)
■ abbreviation
(in writing) amp(s)