Definitions

1. noun

A subphylum of chordates that includes tunicates and lancelets, characterized by a notochord in the larval stage but not in the adult.

“The urochord subphylum is a fascinating example of evolutionary adaptation in marine animals.”

2. noun

A type of chordate that has a notochord only in the larval stage, such as a tunicate or a lancelet.

“The urochord, a simple but intriguing chordate, has been a subject of interest for marine biologists.”