hypertonicity vs tonicity

hypertonicity and tonicity both are nouns.

Word	Noun	Adjective	Verb	Adverb
hypertonicity	Yes	No	No	No
tonicity	Yes	No	No	No

As nouns, tonicity is a hypernym of hypertonicity; that is, tonicity is a word with a broader meaning than hypertonicity:

hypertonicity: (of muscular tissue) the state of being hypertonic
tonicity: the elastic tension of living muscles, arteries, etc. that facilitate response to stimuli

Other hypernyms of hypertonicity include tone, tonus.

hypertonicity (noun)	tonicity (noun)
(of muscular tissue) the state of being hypertonic	the elastic tension of living muscles, arteries, etc. that facilitate response to stimuli
(of a solution) the extent to which a solution has a higher osmotic pressure than some other