From Longman Dictionary of Contemporary Englishpetticoatpet‧ti‧coat /ˈpetikəʊt $ -koʊt/ noun [countable] British EnglishDCC a piece of women’s underwear like a thin skirt or dress that is worn under a skirt or dress SYN slip
Examples from the Corpus
petticoat• Under our summer dresses we wore full petticoats with hoops and white high heels.• He knelt on the floor and pulled off her petticoat.• Her skirt dropped, leaving her standing in petticoat shreds.• The layette also consists of three nightdresses, three vests, three petticoats and two day dresses.• A white petticoat danced as she lifted her bare right leg.• A white petticoat, black stockings and white drawers lay over outer clothes.• If it was cold she padded herself with petticoats which she put on over her nightgown.Origin petticoat (1400-1500) petty “small” + coat 