Definition of pectoral fin in US English:

pectoral fin


  • Each of a pair of fins situated on either side just behind a fish's head, helping to control the direction of movement during locomotion. They correspond to the forelimbs of other vertebrates.

    • ‘Paired pectoral fins and a dorsal fin were present, and the caudal fin was asymmetrical with a large upper lobe.’
    • ‘One of the fossil's most intriguing aspects is the large, paired spines on the shark's pectoral fins, the side fins used for steering.’
    • ‘They have strong pectoral fins with spines that are serrated on the outer side.’
    • ‘They have one caudal fin, one dorsal fin, two pelvic fins, one anal fin, and two pectoral fins.’
    • ‘Look at the shape and size of the dorsal fin, pectoral fins, and the caudal fin.’