request vs collection

request and collection both are nouns.

Word	Noun	Adjective	Verb	Adverb
request	Yes	No	Yes	No
collection	Yes	No	No	No

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

request: a formal message requesting something that is submitted to an authority
collection: request for a sum of money

Other hyponyms of request include application, appeal, ingathering, solicitation, demand.

request (noun)	collection (noun)
the verbal act of requesting	the act of gathering something together
a formal message requesting something that is submitted to an authority	a publication containing a variety of works
	request for a sum of money
	several things grouped together or considered as a whole

request (verb)	collection (verb)
express the need or desire for
ask (a person) to do something
inquire for (information)