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1. Radiation; radiant energy: radiometer.
2. Radioactive: radiochemistry.
3. Radio: radiotelephone.
1. (Telecommunications) denoting radio, broadcasting, or radio frequency: radiogram.
2. (General Physics) indicating radioactivity or radiation: radiochemistry; radiolucent.
3. (Nuclear Physics) indicating a radioactive isotope or substance: radioactinium; radiothorium; radioelement.
[from French, from Latin radius ray; see radius]
n., pl. -di•os, n.
1. a system of telecommunication employing electromagnetic waves of a particular frequency range to transmit speech or other sound over long distances without the use of wires.
2. an apparatus for receiving or transmitting radio broadcasts.
3. a message transmitted by radio.adj.
4. pertaining to, used in, or sent by radio.
5. pertaining to electromagnetic radiation having frequencies in the range of approximately 10 kHz to 300,000 MHz: radio waves.v.t.
6. to transmit (a message, music, etc.) by radio.
7. to send a message to (a person) by radio.v.i.
8. to transmit a message, music, etc., by radio.
[1910–15; shortening of radiotelegraph or radiotelegraphy]
a combining form with the meanings “radiant energy” (radiometer), “radio waves” (radiophotograph ), “emission of rays as a result of the breakup of atomic nuclei” (radioactivity), “x-rays” (radiotherapy).
[< French, comb. form representing Latin radius beam]