A

A¹

(also a)

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.

Phrases

from A to B from one's starting point to one's destination.

from A to Z over the entire range.

————————

A²

abbreviation

1》 (in card games) ace.

2》 (in showing goals or points conceded) against.

3》 ampere(s).

4》 (Å) ångström(s).

5》 answer.

6》 (in names of sports clubs) Athletic.

7》 attack (in designations of US aircraft types): an A-10.

8》 Austria (international vehicle registration).