Ra`di*om"e*ter (?), n. [L. radius radius + -meter: cf. F. radiometre.]
1. Naut.
A forestaff.
2. Physics
An instrument designed for measuring the mechanical effect of radiant energy.
⇒ It consists of a number of light discs, blackened on one side, placed at the ends of extended arms, supported on an a pivot in an exhausted glass vessel. When exposed to rays of light or heat, the arms rotate.
© Webster 1913.