Definition of pleuronectoid in US English:

pleuronectoid

noun

Zoology
  • A fish of the order Pleuronectiformes or the suborder Pleuronectoidei; a flatfish.

adjective

Zoology
  • Resembling flatfishes of the genus Pleuronectes; of or relating to the order Pleuronectiformes or the suborder Pleuronectoidei.

Origin

Mid 19th century; earliest use found in Theodore Gill (1837–1914). From scientific Latin Pleuronectes + -oid. With use as noun compare slightly earlier pleuronect and pleuronectid; with use as adjective compare slightly later pleuronectid.