icebreaker  
noun [ C ] uk/ˈaɪsˌbreɪ.kər/ us/ˈaɪsˌbreɪ.kɚ/
  (ACTIVITY)     
  (彼此不认识的人见面时)活跃气氛的游戏(或笑话)
a game or joke that makes people who do not know each other feel more relaxed together
   (SHIP)     
 破冰船
a strong ship that can break a passage through ice