柯林斯词典pectoral fin 1. N either of a pair of fins, situated just behind the head in fishes, that help to control the direction of 胸鳍 返回 pectoral fin剑桥词典the fin on each side of a fish near the front of its body , used for controlling the direction the fish goes in and for slowing it down 胸鳍（鱼身体前面两侧的鳍，用于控制和减速） 返回 pectoral fin