Source : Webster's Revised Unabridged Dictionary (1913)

Piccadil \Pic"ca*dil\, Piccadilly \Pic`ca*dil"ly\, n. [OF.
   piccagilles the several divisions of pieces fastened together
   about the brim of the collar of a doublet, a dim. fr. Sp.
   picado, p. p. of picar to prick. See {Pike}.]
   A high, stiff collar for the neck; also, a hem or band about
   the skirt of a garment, -- worn by men in the 17th century.