• Webster's Revised Unabridged Dictionary
    • n Radiophony (Physics) The art or practice of using the radiophone.
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Century Dictionary and Cyclopedia
    • n radiophony The production of sound by the action of an intermittent beam of radiant heat; that branch of acoustics which considers sound so produced. For example, if the beam from a lime-light is thrown upon a rotating disk perforated with a series of holes, and, after thus being rendered intermittent, is made to fall upon a confined mass of a liquid or gas capable of absorbing radiant heat, a musical note is obtained from the latter whose pitch depends upon the rapidity of the rotation. Similar results are obtained with a plate of an appropriate solid, as hard rubber. Radiophony also includes the more complex case where an intermittent beam of light, falling upon a substance like selenium (also in a less degree sulphur), serves to vary its electrical resistance, and hence the strength of current passing through it, so as to produce a corresponding sound in a telephone-receiver placed in the circuit. This is illustrated in the photophone.
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Chambers's Twentieth Century Dictionary
    • ns Radiophony the production of sound by radiant heat
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In literature:

The boys read every word of the letter, and were more than ever impressed by the wonderful possibilities of radiophony.
"The Radio Boys at the Sending Station" by Allen Chapman