Either of the bony growths projecting from the upper part of the head of certain hoofed mammals, such as cattle, sheep, and goats. The horns of these animals are never shed, and they consist of bone covered by keratin.
A hard growth that looks like a horn, such as an antler or a growth on the head of a giraffe or rhinoceros. Unlike true horns, antlers are shed yearly and have a velvety covering, and the horns of a rhinoceros are made not of bone but of hairy skin fused with keratin.
The hard durable substance that forms the outer covering of true horns. It consists of keratin.