petticoat

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

• noun A girl's or woman's undergarment, worn under a dress or skirt, that is often full and trimmed with ruffles or lace.
• adjective Relating to or characteristic of women.

from The Century Dictionary.

• noun A short coat or garment worn by men under the long overcoat.
• noun A skirt: formerly, the skirt of a woman's dress or robe, frequently worn over a hoop or farthingale; now, an underskirt worn by women and children; also, in the plural, skirts worn by very young boys.
• noun A woman; a female.
• noun A garment worn by fishermen in warm weather, made of oilcloth or coarse canvas, very wide and descending to the calf of the leg, generally with an insertion for each leg, but sometimes like a woman's petticoat, with no intersecting seam, and worn over the common dress.
• noun In archery, the ground of a target, beyond the white. Also called
• noun The depending skirt or inverted cup-shaped part of an insulator for supporting telegraph-lines, the function of which is to protect the stem from rain.
• Of or pertaining to petticoats; feminine; female: as, petticoat influence.
• noun In electricity, on an insulator for outdoor service, a downward projecting mantle intended to shed the rain-water.

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

• noun (Zoöl.) A loose under-garment worn by women, and covering the body below the waist.
• noun [Colloq.] government by women, whether in politics or domestic affairs.
• noun (Locomotives) a short, flaring pipe surrounding the blast nozzle in the smoke box, to equalize the draft.

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

• noun historical A tight, usually padded undercoat worn by men over a shirt and under the doublet.
• noun historical A woman's undercoat, worn to be displayed beneath an open gown.
• noun A type of ornamental skirt or underskirt, often displayed below a dress; chiefly in plural, designating a woman's skirts collectively.
• noun A light woman's undergarment worn under a dress or skirt, and hanging either from the shoulders or (now especially) from the waist; a kind of slip, worn to make the skirt fuller, or for extra warmth.

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

• noun undergarment worn under a skirt