hydromancy vs foretelling

hydromancy and foretelling both are nouns.

Word	Noun	Adjective	Verb	Adverb
hydromancy	Yes	No	No	No
foretelling	Yes	No	No	No

As nouns, foretelling is a hypernym of hydromancy; that is, foretelling is a word with a broader meaning than hydromancy:

hydromancy: divination by water (as by patterns seen in the ebb and flow of the tides)
foretelling: the art or gift of prophecy (or the pretense of prophecy) by supernatural means

Other hypernyms of hydromancy include divination, fortune telling, soothsaying.

hydromancy (noun)	foretelling (noun)
divination by water (as by patterns seen in the ebb and flow of the tides)	the art or gift of prophecy (or the pretense of prophecy) by supernatural means
	a statement made about the future