Definitions

1. noun

A type of extinct marine animal, particularly a type of extinct echinoderm, that lived during the Cambrian period.

“The discovery of the ctenocyst at the fossil site has shed new light on the evolution of marine life during the Cambrian period.”

2. noun

In some classifications, a type of extinct echinoderm related to the starfish or sea urchin.

“The ctenocyst is an example of a primitive echinoderm that has since become extinct.”