Webster’s Revised Unabridged Dictionary · 1913
Trephine
Tre·phine′, n. [A dim. of 1st trepan: cf. F. tréphine.] (Surg.) An instrument for trepanning, being an improvement on the trepan. It is a circular or cylindrical saw, with a handle like that of a gimlet, and a little sharp perforator called the center pin.
Tre·phine′, v. t. [imp. & p. p. Trephined; p. pr. & vb. n. Trephining.] To perforate with a trephine; to trepan.