'Placoderm' definitions:
Definition of 'placoderm'
From: WordNet
noun
Fish-like vertebrate with bony plates on head and upper body; dominant in seas and rivers during the Devonian; considered the earliest vertebrate with jaws
Definition of 'Placoderm'
From: GCIDE
- Placoderm \Plac"o*derm\, n. [Gr. pla`x, plako`s, tablet + de`rma skin.] (Paleon.) One of the Placodermi. [1913 Webster]