Definitions

1. noun

a person who trephines, especially in a primitive or ancient culture, or a tool used for this purpose, typically a circular saw or drill used to remove a portion of the skull.

“The archaeologists discovered a trepan in the ancient temple, which was used for rituals.”

2. verb

to cut or bore into (an organ or bone), especially by surgical means.

“The surgeon trepanned the patient’s skull to relieve pressure on the brain.”