Word Study
tonus
CIDE DICTIONARY
tonus, n. [L. a sound, tone. See Tone.].
Tonicity, or tone; as, muscular tonus. [1913 Webster]
THESAURUS
tonus
adaptability, bounce, bounciness, buoyance, buoyancy, elasticity, extensibility, flexibility, give, liveliness, rebound, resilience, resiliency, responsiveness, snap, spring, springiness, stretch, stretchability, stretchiness, tone, tonicityFor further exploring for "tonus" in Webster Dictionary Online