What is "spherometer"

Spherometer \Sphe*rom"e*ter\, n. [Sphere + -meter: cf. F. sph['e]rom[`e]tre.] (Physics) An instrument for measuring the curvature of spherical surface, as of lenses for telescope, etc.

n. A device used to measure the curvature of a surface, such as a lens.

n. a measuring instrument for measuring the curvature of a surface

A spherometer is an instrument for the precise measurement of the radius of a sphere. Originally, these instruments were primarily used by opticians to measure the curvature of the surface of a lens.