flipper

nouns

a shoe for swimming; the paddle-like front is an aid in swimming (especially underwater)
fin, flipper
is derived from
flip
the flat broad limb of aquatic animals specialized for swimming
flipper
is derived from
flip
is a part of
animal living wholly or chiefly in or on water
aquatic vertebrate
is a part of
whales and dolphins; manatees and dugongs; walruses; seals
aquatic mammal
is a type of (narrower)
one of the jointed appendages of an animal used for locomotion or grasping: arm; leg; wing; flipper
limb