[SE piccadill, an ornamented collar fashionable in the early 17C. The term comes from the Sp. picadillo, the dimin. of picado, meaning pricked, pierced, punctured, slashed or minced (thus picada, a puncture and picadillo, minced meat). The piccadill was brought to the UK either by Robert Baker (The London Encyclopedia, 1983) or by ‘one Higgins’ (The Atheneum, 1901). Whatever the name, the individual in question made a fortune from his import, sufficient to buy land around what is now Piccadilly Circus and to erect, c.1622, a large mansion which was promptly and irreverently christened Piccadilly Hall. The surrounding area soon became known as Piccadilly. However, the OED cites a source writing in 1656 who claimed that the house was thus named because, being at the furthest edge of the parish of St Martin in the Fields, in which it lay, it was therefore serving as a ‘collar’, or outer edge of the area]
a hangman’s noose.
J. Taylor ‘Superbiae Flagellum’ in Works (1869) I 34: Or one that at the gallowes made her Will, / Late choaked with the Hangmans Pickadill.