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.
[1913 Webster]