Bycocket
Picard wearing a bycocket
A bycocket as part of a costume
A bycocket was a type of feathered hat worn by Robin Hood.
In 2367, Jean-Luc Picard wore a bycocket hat while in Q's simulation of Sherwood Forest and Nottingham. (TNG: "Qpid")
In 2381, a Human Starfleet commander from the training program Klingon Encounter wore a light green bycocket with a yellow feather. (LD: "I, Excretus")