late 13c., "sound made by the human mouth," from Old French voiz, from Latin vocem (nominative vox) "voice, sound, utterance, cry, call, speech, sentence, language, word," related to vocare "to call," from PIE root *wekw- "give vocal utterance, speak" (cf. Sanskrit vakti "speaks, says," vacas- "word;" Avestan vac- "speak, say;" Greek eipon (aorist) "spoke, said," epos "word;" Old Prussian wackis "cry;" German er-wähnen "to mention").
Replaced Old English stefn. Meaning "ability in a singer" is first attested c.1600. Meaning "expression of feeling, etc." (in reference to groups of people, etc., e.g. Voice of America) is recorded from late 14c.