Definitions

1. noun

Any member of the subphylum Tunicata, which includes the sea squirts and other marine creatures that are characterized by their ability to absorb nutrients.

“The biologist studied the behavior of various ascidian species in their natural habitat.”

2. noun

A type of marine animal that is characterized by its ability to filter-feed on plankton and small organisms.

“The ascidian colony was thriving in the shallow waters of the coral reef.”