Webster's Revised Unabridged Dictionary · 1913

Tunicle

Tunicle , noun

[Latin tunicula a little tunic, coat, or membrane, dim. of tunica a tunic: compare Old French tunicle.]

1.
A slight natural covering; an integument.
The tunicles that make the ball or apple of the eye. — Holland
2.
(Roman Catholic Church) A short, close-fitting vestment worn by bishops under the dalmatic, and by subdeacons.