Short definition
Voice search is any query made via a voice assistant (Siri, Alexa, Google Assistant, ChatGPT Voice) rather than typed into a search box.
In depth
Voice queries are longer, more conversational, and more often local than text queries. They typically pull a single answer, so winning voice search means winning the featured snippet, the AI Overview, or the assistant's direct read. Optimizations: question-and-answer copy, FAQPage schema, speakable schema markup, fast page speed, and concise answers under 30 words. Local voice queries lean heavily on GBP data.
Example
A dentist's FAQ 'How much is a teeth cleaning in [city]?' is read aloud by Google Assistant when locals ask the question voicewise.