Cunning and artifice in general.
Military deception or artifice.
A tactic or artifice designed to gain the upper hand, especially one involving underhanded dealings or deception.
Specifically, such a tactic or artifice in military operation.
A surgical instrument with a cylindrical blade used to remove a circular section of tissue, f.e. bone or cornea; a trepan.
To use a trephine during surgery.
To perforate with a trephine.