"A contractile quality inhering in a bearer by virtue of the bearer's elastic tension that facilitate response to stimuli."^^ . . . . "PATO:0001439"^^ . "tone"^^ . . "quality"^^ . . "tonicity"^^ . . "PATO:0001498"^^ . "TODO: we need a clearer differentium between this and contractility - or merge?"^^ .