A rank, normally the highest rank, on any of various scales that assign letters. / (education) The highest letter grade assigned (disregarding plusses and minuses).

Ace. (including in card games) / Acre. / Adult; as used in film rating. / Ammeter. / (physics) Angstrom. / Answer. / (sports) An assist. / (sexuality) Asexual. / (UK, London) Arsehole. / (weaponry) Atom.

(weaponry) Atom; atomic.

(Australia, simile, informal) Very dry, extremely dry. / (Australia, simile, informal) Very thirsty.

(idiomatic, informal) A level of effort beyond what one can usually sustain; great exertion.

In the style or manner of.

Initialism of anno mundi. / Initialism of Master of Arts.

Alternative form of a.m. (“before noon”).

Abbreviation of Alberta, a province of Canada. / Initialism of Artium baccalaureus.

Initialism of able seaman; able-bodied seaman. / Initialism of adult baby. / Initialism of afterburner. / Initialism of aid to the blind. / (military, aviation) Initialism of airbase.