from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Chiefly British A felt hat with a low, rounded crown, similar to a derby.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A felt hat with a rounded crown, similar to a bowler.
from the GNU version of the Collaborative International Dictionary of English
- A round, low-crowned felt hat; a wideawake.
from The Century Dictionary and Cyclopedia
- n. A stiff, round, low-crowned felt hat: often called a billycock hat. Also spelled billicock.
Perhaps from earlier bullycocked, cocked in the fashion of a swashbuckler : bully1, gallant figure + cock1.(American Heritage® Dictionary of the English Language, Fourth Edition)
Apparently an alteration of earlier bully-cocked. (Wiktionary)