1911 Encyclopædia Britannica/Petticoat
PETTICOAT, an underskirt, as part of a woman’s dress. The petticoat, i.e. “petty-coat” or small coat, was originally a short garment for the upper part of the body worn under an outer dress; in the Promptorium parvulorum the Latin equivalent is tunicula. It was both a man’s and a woman’s garment, and was in the first case worn as a small coat under the doublet and by women apparently as a kind of chemise. It was however, early applied to the skirt worn by women hanging from the waist, Whether as the principal lower garment or as an underskirt. In the middle of the 17th century the wide breeches with heavy lace or embroidered ends worn by men were known as “petticoat breeches,” a term also applied to the loose canvas or oilskin overalls worn by fishermen.