What is "radiomicrometer"

Radiomicrometer \Ra`di*o*mi*crom"e*ter\ (r[=a]`d[i^]*[-o]*m[-i]*kr[o^]m"[-e]*t[~e]r), n. [Radio- + micrometer.] (Physics) A very sensitive modification or application of the thermopile, used for indicating minute changes of radiant heat, or temperature.

n. a device used to measure small changes in radiant heat, or in temperature

n. radiometer that is extremely sensitive