A platelike thickening of the epithelial layer of an embryo from which an organ, especially a sense organ, develops.

plural of placode

Of or related to a placode

Alternative spelling of preplacode

plural of placoderm

(paleontology) A member of an extinct class (Placodermi) of jawed fish with armored heads and thoraces; the group lived during the Silurian and Devonian periods.

(paleontology) Pertaining to the class Placodermi.

(zoology) Of, or relating to, prehistoric armoured fishes in the class Placodermi.