flock vs crowd

flock and crowd both are nouns.

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

As nouns, crowd is a hypernym of flock; that is, crowd is a word with a broader meaning than flock:

flock (noun)	crowd (noun)
a group of birds	a large number of things or people considered together
a group of sheep or goats	an informal body of friends
a church congregation guided by a pastor
an orderly crowd
(often followed by `of') a large number or amount or extent

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