crowd vs crowd together

crowd is a noun but crowd together is not a noun.

Word	Noun	Adjective	Verb	Adverb
crowd	Yes	No	Yes	No
crowd together	No	No	Yes	No

As verbs, crowd and crowd together are synonyms defined as:

crowd (noun)	crowd together (noun)
a large number of things or people considered together
an informal body of friends

crowd (verb)	crowd together (verb)
to gather together in large numbers	to gather together in large numbers
cause to herd, drive, or crowd together
approach a certain age or speed
fill or occupy to the point of overflowing