Definition of "tailpiece"

An appendage or appendix.  examples

(music, lutherie) An element, often triangular, to which the strings of a violin, guitar, etc. are attached at the lower end of an instrument.  examples

(architecture) A short joist between a header and a wall.  examples

The part of a telescope containing the adjusting device for the eyepiece, etc.  examples

The part of a lock that transmits motion from the hub to the latch bolt.  examples