Definition of ferrules:
(n) :
A band or cap (usually metal) placed around a shaft to reinforce it or to prevent splitting.
(n) :
A band holding parts of an object together.
(n) :
(painting) The pinched metal band which holds the bristles of a paintbrush or the eraser of a pencil to the shaft; a similar band crimped as part of a cable terminal or to terminate a hose.
(n) :
(specifically, climbing) The metal spike at the end of the shaft of an ice axe.
(n) :
(billiards) The plastic band attaching the tip to the cue.
(n) :
A bushing for securing a pipe joint.