ice ‧ break ‧ er /ˈaɪsˌbreɪkə $ -ər/ BrE AmE noun [countable]
1 . something that you say or do to make people less nervous when they first meet:
This game is an effective icebreaker at the beginning of a semester.
⇨ break the ice at ↑ break 1 (29)
2 . a ship that cuts a passage through floating ice