\E*lec"tro*scope\, n. [Electro- + -scope: cf. F.
['e]lectroscope.] (Physics)
An instrument for detecting the presence of electricity, or
changes in the electric state of bodies, or the species of
electricity present, as by means of pith balls, and the like.

{Condensing electroscope} (Physics), a form of electroscope
   in which an increase of sensibility is obtained by the use
   of a condenser.