(in a jewellery setting) a band or coronet-shaped claw that holds an individual stone
2.
mechanical engineering an externally tapered sleeve made in two or more segments and used to grip a shaft passed through its centre when the sleeve is compressed by being inserted in a tapered hole
3.
horology a small collar that supports the inner end of the hairspring
—vb
4.
(tr) jewellery to mount in a collet
[C16: from Old French: a little collar, from col neckband, neck, from Latin collum neck]