Word Study
Rheostat
CIDE DICTIONARY
Rheostat, n. [Gr. "rei^n + stato`s standing still.].
A contrivance for adjusting or regulating the strength of electrical currents, operating usually by the intercalation of resistance which can be varied at will. [1913 Webster]
OXFORD DICTIONARY
Rheostat, n. Electr. an instrument used to control a current by varying the resistance.
Derivative
rheostatic adj.
Etymology
Gk rheos stream + -STAT
For further exploring for "Rheostat" in Webster Dictionary Online