ˈtōnəs noun
( -es )
Etymology: New Latin, from Latin, tension — more at tone
: tone 11a(1) ; usually : the state of partial contraction that is characteristic of normal muscle, is maintained at least in part by a continuous bombardment of motor impulses originating reflexly, and serves to maintain body posture and to hold the musculature in a state of readiness for specific demands — compare clonus