expression
attention!
A command used in schools, military, or sports to order people to stand at attention. Often shouted.
先生が「気をつけ！」と言うと、生徒たちは背筋を伸ばした。
When the teacher said 'Attention!', the students straightened their backs.
expression, noun
standing at attention
The posture or state of standing straight with heels together and arms at the sides. Used as a noun.
We listened to the principal's speech standing at attention.
The command to stand at ease, often paired with 気をつけ in drills.
A more general term for 'attention' or 'notice', not specifically the standing posture.
From 気 (spirit, attention) + を (object marker) + つけ (imperative form of 付ける, to attach). Literally 'attach your attention/spirit', a set phrase for the command 'attention!'.