— trephination /tref'euh nay"sheuhn/ , n.
/tri fuyn", -feen"/ , n. , v. , trephined, trephining . Surg.
n.
1. 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.
v.t.
2. to operate upon with a trephine.
[ 1620-30; sp. var. of trefine, orig. trafine, b. trapan (var. of TREPAN 1 ) and L phrase tres fines three ends (the inventor's explanation) ]