From Longman Dictionary of Contemporary Englishicebreakerice‧break‧er /ˈaɪsˌbreɪkə $ -ər/ noun [countable] 1 FRIENDLYsomething 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 TTWa ship that cuts a passage through floating ice
Examples from the Corpus
icebreaker• Eddie has scored her first basket, an icebreaker that helps her self-confidence.• Excellent fun and a good icebreaker for the kids.• A baby is a powerful icebreaker, and Charlie is especially charming in this regard. 