nRadiophony(Physics) The art or practice of using the radiophone.
Century Dictionary and Cyclopedia
nradiophonyThe 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.
Chambers's Twentieth Century Dictionary
nsRadiophonythe production of sound by radiant heat
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