'Trochal disk' definitions:

Definition of 'Trochal disk'

From: GCIDE

Trochal \Tro"chal\, a. [From Gr. ? a wheel.] (Zool.) Resembling a wheel. [1913 Webster]
Trochal disk (Zool.), the cephalic disk of a rotifer. It is usually surrounded by a fringe of cilia. [1913 Webster]