A billy goat.
A good friend.
A billy club.
A male goat; a ram.
A slubbing or roving machine.
A bong for smoking marijuana.
A tin with a swing handle used to boil tea over an open fire; a billycan; a billypot.
A condom.
A type of wild mountain goat of the genus Capra, such as the species Capra ibex.
An imaginary creature with serrated horns, somewhat similar to the heraldic antelope.