• Webster's Revised Unabridged Dictionary
    • n Photophone (Physics) An apparatus for the production of sound by the action of rays of light.
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Century Dictionary and Cyclopedia
    • n photophone An instrument by which a beam of light may be made to transmit spoken words to a distance. One form consists of a thin mirror of silvered mica which receives the vibrations from the person speaking, and upon which a beam of light falls at the same time. This light is reflected to the receiving-point at a distance. There it falls upon a concave mirror, and is brought to a focus upon a selenium-cell. The variation in the light produces a corresponding variation in the electrical resistance of the selenium, and this reproduces the spoken words in a telephone connected with it.
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Chambers's Twentieth Century Dictionary
    • n Photophone fō′tō-fōn an apparatus for transmitting articulate speech to a distance along a beam of light.
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Webster's Revised Unabridged Dictionary
Photo-, + Gr. sound
Chambers's Twentieth Century Dictionary
Gr. phōs, phōtos, light, phōnē, sound.


In literature:

This is the phenomenon which, as you know, has been utilized by Prof. Graham Bell in that most ingenious and striking invention, the photophone.
"Scientific American Supplement No. 275" by Various