tunic

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A loose-fitting garment, sleeved or sleeveless, extending to the knees and worn by men and women especially in ancient Greece and Rome.
• noun A medieval surcoat.
• noun A long, plain, close-fitting jacket, usually having a stiff high collar and worn as part of a uniform.
• noun A loose-fitting women's garment that falls to the hip or thigh and is often worn over leggings or pants.
• noun Anatomy A coat or layer enveloping an organ or part.
• noun Botany A loose membranous outer covering of a bulb or corm, as of an onion, tulip, or crocus.

from The Century Dictionary.

• noun In Roman antiquity, a garment like a shirt or gown worn by either sex, very often an undergarment: hence a general term applied to garments, of all periods and materials, which are worn depending from the neck, whether girded at the waist or not, or kept in place by other garments worn outside of them, and whether such garments are long and full or short and scant.
• noun At the present time, a garment generally loose, but gathered or girded at the waist, worn by women, usually an outer garment; a sort of wrap or coat for street wear.
• noun Eccles., a vestment worn over the alb in the Roman Catholic Church and in some Anglican churches by the subdeacon or epistler at the celebration of the mass or holy communion.
• noun A military surcoat.
• noun In the British army, the ordinary fatigue-coat: applied usually to the coat of a private, but sometimes to that of an officer.
• noun A natural covering; an integument.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Rom. Antiq.) An under-garment worn by the ancient Romans of both sexes. It was made with or without sleeves, reached to or below the knees, and was confined at the waist by a girdle.
• noun Any similar garment worn by ancient or Oriental peoples; also, a common name for various styles of loose-fitting under-garments and over-garments worn in modern times by Europeans and others.
• noun (R. C. Ch.) Same as Tunicle.
• noun (Anat.) A membrane, or layer of tissue, especially when enveloping an organ or part, as the eye.
• noun (Bot.) A natural covering; an integument.
• noun (Zoöl.) See Mantle, n., 3 (a).

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A garment worn over the torso, with or without sleeves, and of various lengths reaching from the hips to the ankles.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun an enveloping or covering membrane or layer of body tissue
• noun any of a variety of loose fitting cloaks extending to the hips or knees