Named after Piccadilly, which recalls 'piccadills', fashionable collars of the early 1600s.
Around 1611 or 1612 a tailor, Robert Baker, who prospered by making and selling piccadills, bought land here; within two years his house was known as Pickadilly Hall. The street was later named Portugal Street, but Piccadilly won out. The circus, from the Latin for 'circle', a round space at a junction, was built in 1819 as Regent Circus South.