tunicle
noun
tu·ni·cle ˈtü-ni-kəl 
ˈtyü-
: a short vestment worn by a subdeacon over the alb during mass and by a bishop under the dalmatic at pontifical ceremonies
Word History
Etymology
Middle English, from Anglo-French tonicle, Latin tunicula, diminutive of tunica
First Known Use
14th century, in the meaning defined above