It is the hypothetical source of/evidence for its existence is provided by: Sanskrit avih, Avestan avish "openly, evidently;" Greek aisthanesthai "to feel;" Latin audire "to hear;" Old Church Slavonic javiti "to reveal."
1935, as visual equivalent of audio, from Latin video "I see," first person singular present indicative of videre "to see" (see vision). As a noun, "that which is displayed on a (television) screen," 1937.
Engineers, however, remember the sad fate of television's first debut and are not willing to allow "video transmission" (as television is now called by moderns) to leave the laboratory until they are sure it will be accepted. [The Michigan Technic, November 1937]