Bil"ly*cock (?), n., or Bil"ly*cock hat` (?). [Perh. from bully + cock; that is, cocked like the hats of the bullies.]
A round, low-crowned felt hat; a wideawake.
The undignified billycocks and pantaloons of the West. B. H. Chamberlain.
Little acquiesced, and Ransome disguised him in a
beard, and a loose set of clothes, and a billicock
hat. Charles Reade.
© Webster 1913.