Noun

1. A ship designed to break through ice so that it, or other ships coming behind, can navigate on frozen seas.

   The steel hulls of ice-breakers are much thicker than those of standard vessels.

   • 2005: My father's Bonneville was cutting its way toward us like an icebreaker moving through my whole state of consciousness. — Martin Torgoff, Can't Find My Way Home (Simon & Schuster 2005, p. 11)

2. A game, activity, humourous anecdote, etc., designed to relax a group of people to help them get to know each other.

   The new college hallmates were awkward with each other at first, but after a game of charades as an icebreaker, they were laughing like old friends.