hypotonicity vs hypotonus

hypotonicity and hypotonus both are nouns.

Word	Noun	Adjective	Verb	Adverb
hypotonicity	Yes	No	No	No
hypotonus	Yes	No	No	No

As nouns, hypotonicity and hypotonus are synonyms defined as:

hypotonicity and hypotonus: (of muscular tissue) the state of being hypotonic

Other synonyms of hypotonicity include hypotonia.

hypotonicity (noun)	hypotonus (noun)
(of muscular tissue) the state of being hypotonic	(of muscular tissue) the state of being hypotonic
(of a solution) the extent to which a solution has a lower osmotic pressure than some other