RADIOMICROMETER
Ra`di*o*mi*crom"e*ter, n. Etym: [Radio- + micrometer.] (Physics)
Defn: A very sensitive modification or application of the thermopile, used for indicating minute changes of radiant heat, or temperature.
RADIOPHARE
Ra"di*o*phare, n. [Radio- + phare.]
Defn: A radiotelegraphic station serving solely for determining the position of ships. The radius of operation of such stations was restricted by the International Radiotelegraphic Convention (1912) to 30 nautical miles.
RADIOPHONE
Ra"di*o*phone, Etym: [Radio- + Gr. (Physics)
Defn: An apparatus for the production of sound by the action of luminous or thermal rays. It is essentially the same as the photophone.
RADIOPHONY
Ra`di*oph"o*ny, n. (Physics)
Defn: The art or practice of using the radiophone.
RADIOPTICON
Ra`di*op"ti*con, n. [Radio-+ stereopticon.]
Defn: See Projector, above.