Ra′di‐om″e‐ter (–ŏm″ē̍‐tẽr), n. [L. radius radius + -meter: cf. F. radiomètre.] 1. (Naut.) A forestaff.
2. (Physics) An instrument designed for measuring the mechanical effect of radiant energy.
☞ It consists of a number of light disks, blackened on one side, placed at the ends of extended arms, supported on a pivot in an exhausted glass vessel. When exposed to rays of light or heat, the arms rotate.