Auto-tuner is a device that widely used in the music industry to correct an out-of-tune or off-key vocal performance. It has transformed the way music is produced, and its importance cannot be overemphasized. While the word "auto-tuner" is commonly used to describe this technology, there are other words that can be used interchangeably. Some of these synonyms include pitch shifter, pitch corrector, vocal tuner, and pitch modulator. Each of these words describes a device or software that can automatically adjust the pitch of a vocal performance. It's essential to know these synonyms to communicate effectively and often in the context of music production.