Definitions

1. adjective

Relating to or resembling a placoid scale, especially one that covers the body of an echinoderm, such as a shark or a starfish.

“The placoid scales on the shark’s body provided protection against predators.”

2. noun

A type of scale, especially one that covers an echinoderm.

“The placoids on the sea star’s body helped it move and sense its surroundings.”