low water vs tide

low water and tide both are nouns.

Word	Noun	Adjective	Verb	Adverb
low water	Yes	No	No	No
tide	Yes	No	Yes	No

As nouns, tide is a hypernym of low water; that is, tide is a word with a broader meaning than low water:

low water: the lowest (farthest) ebb of the tide
tide: the periodic rise and fall of the sea level under the gravitational pull of the moon

low water (noun)	tide (noun)
the lowest (farthest) ebb of the tide	the periodic rise and fall of the sea level under the gravitational pull of the moon
	something that may increase or decrease (like the tides of the sea)
	there are usually two high and two low tides each day