trepan vs operation

trepan and operation both are nouns.

Word	Noun	Adjective	Verb	Adverb
trepan	Yes	No	Yes	No
operation	Yes	No	No	No

trepan (noun)	operation (noun)
a drill for cutting circular holes around a center	a medical procedure involving an incision with instruments; performed to repair damage or arrest disease in a living body
a surgical instrument used to remove sections of bone from the skull	(mathematics) calculation by mathematical methods
	activity by a military or naval force (as a maneuver or campaign)
	a planned activity involving many people performing various actions
	a process or series of acts especially of a practical or mechanical nature involved in a particular form of work
	a business especially one run on a large scale
	the activity of operating something (a machine or business etc.)
	(psychology) the performance of some composite cognitive activity; an operation that affects mental contents
	(computer science) data processing in which the result is completely specified by a rule (especially the processing that results from a single instruction)
	process or manner of functioning or operating
	the state of being in effect or being operative

trepan (verb)	operation (verb)
cut a hole with a trepan, as in surgery