security system vs computing

security system and computing both are nouns.

Word	Noun	Adjective	Verb	Adverb
security system	Yes	No	No	No
computing	Yes	No	No	No

security system (noun)	computing (noun)
an electrical device that sets off an alarm when someone tries to break in	the procedure of calculating; determining something by mathematical or logical methods
(computing) a system that enforces boundaries between computer networks	the branch of engineering science that studies (with the aid of computers) computable processes and structures