To make a hole in (something); to hollow.
To uncover (something) by digging.
To remove part of (something) by scooping or digging it out.
Any member of a major grouping of unicellular eukaryotes, of the clade Excavata.
To perforate with a trephine.
To use a trephine during surgery.
A surgical instrument with a cylindrical blade used to remove a circular section of tissue, f.e. bone or cornea; a trepan.