flipper
/ˈflɪpə(r)/noun
1- a broad flat limb without fingers, used for swimming by various sea animals such as seals, whales, and turtles（海豹、鲸、海龟等的）鳍状肢, 鳍足。
1.1
- a flat rubber attachment worn on the foot for underwater swimming（潜水用）脚蹼, 鸭脚板。
1.2
- a pivoted arm in a pinball machine, controlled by the player and used for sending the ball back up the table（弹球机玩者操纵的）回弹转臂, 回弹枢轴。