A tunic is a loose-fitting shirt that looks sort of like a long shirt or a short dress. For a fashionable summer look, you might pair trousers with a comfortable tunic that extends past your waist.
The ancient Greeks and Romans were early fans of the tunic, and the loose-fitting garment remains popular in modern times. A tunic is popular wardrobe choice in hot, tropical regions because it's loose fitting and comfortable and helps you stay cool. Tunic can also refer to a membrane or tissue that covers something, like an organ or part of a plant. Some plants like tulips and onions have a protective tunic covering the outside of their bulb.