depend vs dependency

depend is not a noun while dependency is a noun.

Word	Noun	Adjective	Verb	Adverb
depend	No	No	Yes	No
dependency	Yes	No	No	No

depend (noun)	dependency (noun)
	a geographical area politically controlled by a distant country
	the state of relying on or being controlled by someone or something else
	being abnormally tolerant to and dependent on something that is psychologically or physically habit-forming (especially alcohol or narcotic drugs)

depend (verb)	dependency (verb)
have faith or confidence in
be contingent upon (something that is elided)