TREPHINING
Verb
trephining
present participle of trephine
Noun
trephining (plural trephinings)
The use of a trephine.
Source: Wiktionary
TREPHINE
Tre*phine", n. Etym: [A dim. of 1st trepan: cf. F. tréphine.] (Surg.)
Definition: 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.]
Definition: To perforate with a trephine; to trepan.
Source: Webster’s Unabridged Dictionary 1913 Edition