ICEBREAKER

icebreaker

(noun) a beginning that relaxes a tense or formal atmosphere; “he told jokes as an icebreaker”

icebreaker, iceboat

(noun) a ship with a reinforced bow to break up ice and keep channels open for navigation

Source: WordNet® 3.1

Etymology

Noun

icebreaker (plural icebreakers)

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

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

(theater) A lively song and dance routine at the start of a musical.

Source: Wiktionary