TONICITY
tonicity, tonus, tone
(noun) the elastic tension of living muscles, arteries, etc. that facilitate response to stimuli; “the doctor tested my tonicity”
Source: WordNet® 3.1
Etymology
Noun
tonicity (plural tonicities)
(medicine) The normal presence of tone or tension in a muscle or organ; tonus
(sciences) The ability of a solution to exert an osmotic pressure upon a membrane
Source: Wiktionary
To*nic"i*ty, n. (Physiol.)
Definition: The state of healty tension or partial contraction of muscle
fibers while at rest; tone; tonus.
Source: Webster’s Unabridged Dictionary 1913 Edition