Definition of malacopterygian in US English:

malacopterygian

adjective

Ichthyology
rare
  • Originally: belonging to the group Malacopterygii, comprising bony fishes having fins supported by soft (i.e. segmented and often branched) rays. Later: designating or relating to fishes having such fins.

noun

Ichthyology
rare
  • A malacopterygian fish.

Origin

Mid 19th century; earliest use found in William Kirby (1759–1850), entomologist and naturalist. Probably from French malacoptérygien from malaco- + -ptérygien, after scientific Latin Malacopterygii.

Pronunciation

malacopterygian

/ˌmaləkɒptəˈrɪdʒ(ɪ)ən/