ice·break·er 
(īsbrā′kər)
(īsbrā′kər)n.
1. A sturdy ship built for breaking a passage through icebound waters. Also called iceboat.
2. A protective pier or dock apron used as a buffer against floating ice.
3.
a. Something done or said to relax an unduly formal atmosphere or situation.
b. A beginning; a start.
icebreak′ing n.