highwater vs springtide

highwater and springtide both are nouns.

Word	Noun	Adjective	Verb	Adverb
highwater	Yes	No	No	No
springtide	Yes	No	No	No

As nouns, springtide is a hyponym of highwater; that is, springtide is a word with a more specific, narrower meaning than highwater:

highwater: the tide when the water is highest
springtide: a greater than average tide occurring during the new and full moons

Other hyponyms of highwater include direct tide, neap, neap tide.

highwater (noun)	springtide (noun)
the tide when the water is highest	a greater than average tide occurring during the new and full moons
	a swelling rush of anything