1922 Joyce Ulysses 360He could see her other things too, nainsook knickers, the fabric that caresses the skin, better than those other pettiwidth, the green, four and eleven, on account of being white.
Ibid. 544Lifting up her pettigown and folding a half sovereign into the top of her stocking.
1923 Dialect Notes V. 246 Pettibockers, n. pl. A loose garment for girls, worn under skirts: contamination of petticoat and knickerbockers.
1939 Joyce Finnegans Wake iv. 611His yellow saffron pettikilt.
1942 Berrey & Van den Bark Amer. Thes. Slang. §87/27Pettibockers, women's old-fashioned knickerbockers.
1960 Harper's Bazaar Apr. 11 Nightdresses, slips, pettiskirts, panties.
1963 Seventeen Aug. 32 A new word in lingerie. Pettisets (a petti-top matched with petti-pants as well as a petticoat).
1964 N.Y. Post 7 Oct. 13Perfect under your swinging skirts, pettipants fashioned with a divided skirt.
1968 J. Ironside Fashion Alphabet 71Pettipants, petticoat and pants combined.
1970 N. Armstrong et al. First on Moon vi. 126They found a present for Jan's friend—pettipants edged with green lace.
1972 Daily Tel. (ColourSuppl. ) 13 Oct. 16/1On top of this I wore a petti-blouse (which is a blouse and a petticoat).
ORIGIN: from petticoat .