- to make flat.
- to knock down: The boxer flattened his opponent in the second round.
- to become flat.
- flat1 (def. 61).
- to fly into a horizontal position, as after a dive.
- to make or become flat or flatter
- (tr) informal
- to knock down or injure; prostrate
- to crush or subdue
- to lower the pitch of (a note) by one chromatic semitone
- to manoeuvre an aircraft into horizontal flight, esp after a dive
