collection vs group

collection and group both are nouns.

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

As nouns, group is a hypernym of collection; that is, group is a word with a broader meaning than collection:

Other hypernyms of collection include grouping.

collection (noun)	group (noun)
the act of gathering something together	any number of entities (members) considered as a unit
a publication containing a variety of works	a set that is closed, associative, has an identity element and every element has an inverse
request for a sum of money	(chemistry) two or more atoms bound together as a single unit and forming part of a molecule
several things grouped together or considered as a whole

collection (verb)	group (verb)
	arrange into a group or groups
	form a group or group together