Merriam-Webster's Collegiate® Dictionary, 11th Edition
PETTICOAT
I. noun
Etymology: Middle English petycote short tunic, petticoat, from pety small + cote coat
Date: 15th century
a skirt worn by women, girls, or young children: as, an outer skirt formerly worn by women and small children, a fancy skirt made to show below a draped-up overskirt, an underskirt usually a little shorter than outer clothing and often made with a ruffled, pleated, or lace edge, the skirt of a woman's riding habit,
2. a garment characteristic or typical of women, woman , something (as a valance) resembling a petticoat, petticoated adjective
II. adjective
Date: 1660
of, relating to, or exercised by women ; female