Definition of tail-bone:
(n) :
(anatomy) The caudal appendage of an animal that is attached to their posterior and near the anus or cloaca.
(n) :
An object or part of an object resembling a tail in shape, such as the thongs on a cat-o'-nine-tails.
(n) :
The back, last, lower, or inferior part of anything.
(n) :
The feathers attached to the pygostyle of a bird.
(n) :
The tail-end of any object.
(n) :
The rear structure of an aircraft, the empennage.