placoderm Meaning, Definition & Usage
- 
       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
        
      
 
WordNet
Plac"o*derm noun
Etymology
Gr. , , tablet + skin.Definitions
- (Paleon.) - One of the Placodermi.