col·let 
(kŏlĭt)
(kŏlĭt)n.
1. A cone-shaped sleeve used for holding circular or rodlike pieces in a lathe or other machine.
2. A metal collar used in watchmaking to join one end of a balance spring to the balance staff.
3. A circular flange or rim, as in a ring, into which a gem is set.
[French, diminutive of col, collar, from Latin collum, neck; see kwel-1 in the Appendix of Indo-European roots.]