interjection
as you were; return to original position
Used as a command in drills, calisthenics, or military contexts to tell someone to go back to their starting posture.
「もとい！」と号令がかかり、全員が元の姿勢に戻った。
"As you were!" came the command, and everyone returned to their original position.
interjection
er, rather; I mean
Used in speech to correct oneself immediately after a mistake, similar to 'I mean' or 'or rather'.
See also: 元へ
明日、いや、もとい、明後日にお会いしましょう。
Let's meet tomorrow—er, rather, the day after tomorrow.
Derived from 元 (もと, 'origin') + い, an imperative form of いる (to be), literally meaning 'be as before'. The correction sense developed from the idea of returning to a previous, correct state.