—n.
1 a cylindrical saw formerly used by surgeons for removing part of the bone of the skull.
2 a borer for sinking shafts.
—v.tr. (trepanned, trepanning) perforate (the skull) with a trepan.
Derivatives:
trepanation n. trepanning n.
Etymology: ME f. med.L trepanum f. Gk trupanon f. trupao bore f. trupe hole
Useful english dictionary. 2012.