Definition of pelvic fin in English:

pelvic fin

noun

Zoology
  • Each of a pair of fins on the underside of a fish's body, attached to the pelvic girdle and helping to control direction.

    Also called ventral fin
    • ‘The body is long and snake-like, lacking caudal, dorsal and pelvic fins.’
    • ‘Often frogfish walk, using the two pectoral fins and pelvic fins.’
    • ‘They have one caudal fin, one dorsal fin, two pelvic fins, one anal fin, and two pectoral fins.’
    • ‘The posterior part of their caudal fin and pelvic fins are black.’
    • ‘Small deviations from the natural model were made in the pectoral fins, the size of the dorsal and anal fins, and the omission of the first dorsal fin, pelvic fins and finlets.’