A long, loose fitting top worn over a skirt is an example of a tunic.
A short coat worn by a police officer is an example of a tunic.
Origin of tunic
- Middle English tunik from Old French tunique from Latin tunica of Phoenician origin Hebrew kuttōnet, kətōnet from Central Semitic kuttān, *kittān chiton
From American Heritage Dictionary of the English Language, 5th Edition