selection vs decision

selection and decision both are nouns.

Word	Noun	Adjective	Verb	Adverb
selection	Yes	No	No	No
decision	Yes	No	No	No

As nouns, decision is a hyponym of selection; that is, decision is a word with a more specific, narrower meaning than selection:

selection (noun)	decision (noun)
the act of choosing or selecting	the act of making up your mind about something
the person or thing chosen or selected	the trait of resoluteness as evidenced by firmness of character or purpose
a passage selected from a larger work	a position or opinion or judgment reached after consideration
an assortment of things from which a choice can be made	the outcome of a game or contest
a natural process resulting in the evolution of organisms best adapted to the environment	(boxing) a victory won on points when no knockout has occurred