Pronunciation: (tri-fīn', -fēn'), [key]
—n., v., -phined, -phin•ing. Surg.
a small circular saw with a center pin mounted on a strong hollow metal shaft to which is attached a transverse handle: used in surgery to remove circular disks of bone from the skull.
to operate upon with a trephine.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.