cog vs gear

cog and gear both are nouns.

Word	Noun	Adjective	Verb	Adverb
cog	Yes	No	Yes	No
gear	Yes	No	Yes	No

cog (noun)	gear (noun)
tooth on the rim of gear wheel	a toothed wheel that engages another toothed mechanism in order to change the speed or direction of transmitted motion
a subordinate who performs an important but routine function	equipment consisting of miscellaneous articles needed for a particular operation or sport etc.
	wheelwork consisting of a connected set of rotating gears by which force is transmitted or motion or torque is changed
	a mechanism for transmitting motion for some specific purpose (as the steering gear of a vehicle)

cog (verb)	gear (verb)
join pieces of wood with cogs	set the level or character of
roll steel ingots