# Glossary

Short definitions of terms used throughout the API and this documentation.

| Term                   | Description |
|------------------------|-------------|
| **Access token**       | A short-lived bearer token obtained by exchanging an API key at `POST /v1/auth/token`. Used for client-side applications to avoid exposing the API key directly. |
| **API key**            | A secret token used to authenticate requests to the Reson8 API. Scoped to a single client. |
| **Confidence score**   | The model's probability for a recognized word, in `(0, 1]`. Available when `include_confidence` is enabled. |
| **Custom model**       | A named collection of phrases that biases transcription toward domain-specific vocabulary. See [Custom Models](/speech-to-text/features/custom-models/). |
| **Final result**       | A stable transcription that will not change as more audio is received. Indicated by `is_final: true`. |
| **Flush**              | A request to force the server to finalize any buffered audio and return a transcript immediately. The server responds with a flush confirmation. |
| **Interim result**     | A partial transcription that may be revised as more audio is processed. Useful for live feedback during streaming. |
| **Pattern**            | A regex-style description of a short structured token, such as an order code or licence plate, to recover in transcription. See [Patterns](/speech-to-text/features/patterns/). |
| **PCM**                | Pulse-code modulation - a raw, uncompressed audio encoding. The `pcm_s16le` format (16-bit signed, little-endian) is supported when `encoding` is set explicitly. |
| **Phrases**            | Terms that bias transcription toward your vocabulary, passed per request via the `phrases` parameter or collected in a [custom model](/speech-to-text/features/custom-models/). |
| **Segment**            | A per-speaker piece of a diarized prerecorded response, with its own text and speaker ID. See [Diarization](/speech-to-text/features/diarization/). |
| **Session**            | An active WebSocket connection during which audio is streamed and transcriptions are returned. |
| **Speaker ID**         | An integer label for a speaker within a session, assigned in the order speakers are first heard. See [Diarization](/speech-to-text/features/diarization/). |
| **Turn**               | One speaker's stretch of speech in a conversation, opened by `turn_start` and closed by `turn_end`. See [Turns](/speech-to-text/turns/). |
| **Turn end candidate** | An early signal that a turn is ending, carrying the transcript so far. Each candidate replaces the previous one; `turn_end` confirms the last. See [Turns](/speech-to-text/turns/). |
| **Utterance**          | A continuous stretch of speech. With auto-detection, the language is detected per utterance. See [Languages](/speech-to-text/features/languages/). |