hem in vs ebb

hem in is not a noun while ebb is a noun.

Word	Noun	Adjective	Verb	Adverb
hem in	No	No	Yes	No
ebb	Yes	No	Yes	No

As verbs, ebb is a hyponym of hem in; that is, ebb is a word with a more specific, narrower meaning than hem in:

hem in: surround so as to force to give up
ebb: hem in fish with stakes and nets so as to prevent them from going back into the sea with the ebb

Other hyponyms of hem in include blockade, seal off.

hem in (noun)	ebb (noun)
	the outward flow of the tide
	a gradual decline (in size or strength or power or number)

hem in (verb)	ebb (verb)
surround so as to force to give up	fall away or decline
surround in a restrictive manner	hem in fish with stakes and nets so as to prevent them from going back into the sea with the ebb
	flow back or recede