Definition of costal plate in English:

costal plate

noun

Zoology
  • 1Any of the calcified plates forming the sides of the calyx of a crinoid (now rare).

  • 2(In the carapace of a chelonian) any of the bony plates that are located in a row on either side of the neural plates, and are attached beneath to the ribs.

Origin

Early 19th century; earliest use found in Johann Samuel Miller (1779–1830), naturalist and museum curator.