ice‧break‧er /ˈaɪsˌbreɪkə $ -ər/ 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 break¹(29)

2. a ship that cuts a passage through floating ice

[TahlilGaran] Dictionary of Contemporary English ▲