hydrostatics vs hydraulics

hydrostatics and hydraulics both are nouns.

Word	Noun	Adjective	Verb	Adverb
hydrostatics	Yes	No	No	No
hydraulics	Yes	No	No	No

As nouns, hydraulics is a hypernym of hydrostatics; that is, hydraulics is a word with a broader meaning than hydrostatics:

hydrostatics: study of the mechanical properties of fluids that are not in motion
hydraulics: study of the mechanics of fluids

Other hypernyms of hydrostatics include fluid mechanics.

hydrostatics (noun)	hydraulics (noun)
study of the mechanical properties of fluids that are not in motion	study of the mechanics of fluids