A kind of waistcoat or under garment worn by men in ancient Rome and the east. In the later ages of the republic, the tunic was a long garment with sleeves.

Among the religious, a woolen shirt or under garment.

In anatomy, a membrane that covers or composes some part or organ; as the tunics or coats of the eye; the tunics of the stomach, or the membranous and muscular layers which compose it.

A natural covering; an integument; as the tunic of a seed. The tunic of the seed, is the arillus, a covering attached to the base only of the seed, near the hilum or scar, and enveloping the rest of the seed more or less completely and closely.