hypotonia vs tonus

hypotonia and tonus both are nouns.

Word	Noun	Adjective	Verb	Adverb
hypotonia	Yes	No	No	No
tonus	Yes	No	No	No

As nouns, tonus is a hypernym of hypotonia; that is, tonus is a word with a broader meaning than hypotonia:

hypotonia: (of muscular tissue) the state of being hypotonic
tonus: the elastic tension of living muscles, arteries, etc. that facilitate response to stimuli

Other hypernyms of hypotonia include tone, tonicity.

hypotonia (noun)	tonus (noun)
(of muscular tissue) the state of being hypotonic	the elastic tension of living muscles, arteries, etc. that facilitate response to stimuli