The Collaborative International Dictionary of English v.0.48:
dicky-seat \dicky-seat\ n. 1. same as dickie-seat. Syn: dickey, dickie, dicky, dickey-seat, dickie-seat. [WordNet 1.5]WordNet (r) 3.0 (2006):
dicky-seat n 1: a small third seat in the back of an old-fashioned two- seater [syn: dickey, dickie, dicky, dickey-seat, dickie-seat, dicky-seat]