The first letter of the English alphabet, called a and written in the Latin script.

The ordinal number first, derived from this letter of the English alphabet, called a and written in the Latin script.

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

(weaponry) Atom; atomic.

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.

(idiomatic) To assert an opinion or viewpoint; to defend one's point of view or beliefs.

(idiomatic) To show annoyance, or to complain loudly about something, often when it is of little importance in reality.

(idiomatic, chiefly imperative) To be kind or sympathetic; to treat others kindly.

Alternative form of get a rise out of

(chiefly US, transitive, idiomatic) To obtain a reaction from someone, especially one of annoyance.