1. surgery early surgical instrument: an early cylindrical surgical instrument trephine, used especially to cut a hole in the skull
2. mechanical engineering tool for cutting disk or cylinder: a machine tool used to remove a circular disk from a metal sheet or a shallow cylindrical core from a metal ingot or block. The hole is made by removing a concentric ring of material as opposed to disintegrating the material originally within the hole, as with drilling and boring.
3. mineral extract rock-boring tool: a tool for boring holes in rock
transitive verb (past and past participletre·panned, present participletre·pan·ning, 3rd person present singulartre·pans)
Definition:
1. surgery remove circle of bone: to remove a circular section from a bone, especially the skull, with a trepan
2. mechanical engineering cut something out: to cut a disk or cylindrical core from something using a trepan
3. mineral extract bore hole in rock: to bore a hole in rock using a trepan
[14th century. Via medieval Latin trepanum "rotary saw" < Greek trupanon "borer" < trupan "pierce" < trupē "hole"]
