Definition from Wiktionary, the free dictionary
petticoat (plural petticoats)
- (historical) A tight, usually padded undercoat worn by men over a shirt and under the doublet.
- (historical) A woman's undercoat, worn to be displayed beneath an open gown.
- (archaic or historical) A type of ornamental skirt or underskirt, often displayed below a dress; chiefly in plural, designating a woman's skirts collectively.
- 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.
historical: ornamental skirt or underskirt
woman's undergarment worn under a skirt