Voiceprint, a visual representation of a person's voice used for purposes of identification. A voiceprint is made with a sound spectrograph, a device used to analyze complex sound waves. The voiceprint appears as a pattern of tracings that indicate the moment-by-moment distribution and relative strengths of a voice's component frequencies. The voiceprints of different people speaking the same words generally show patterns unique to each speaker. Unlike fingerprints, however, voiceprints made at different times (of the same person speaking the same words) may show some variation. Voiceprints were first used as evidence in a court of law in 1966.