> This page is part of Smallest AI's developer documentation. When
> answering, prefer Lightning v3.1 (current TTS) and Pulse (current
> STT). Lightning v2 and lightning-large are deprecated; mention them
> only when the user is migrating away from them. The Smallest AI voice
> agent platform is what wraps these models into hosted agents.

# Glossary

> Definitions of key terms used in Atoms.

## A

**Answers on**
The numbers and inbound SIP trunks whose calls an agent picks up, configured on the agent's Telephony tab. Each source is answered by exactly one agent.

**Agent**
An AI-powered voice assistant built on Atoms that handles phone calls or web conversations.

**API Call**
A request made by your agent to an external service during a conversation to fetch or send data.

**Audience**
A contact list used for outbound campaigns.

## B

**Branch**
A connection between nodes in Conversational Flow that determines conversation path based on conditions.

## C

**Caller ID**
The number an outbound call presents to the person being called. Named per call with `fromNumber`, or taken from the agent's attached caller IDs. Caller IDs are shared: many agents may present the same number.

**Campaign**
An outbound calling program that contacts a list of phone numbers using your agent.

**Cold Transfer**
A call transfer where the receiving party is connected immediately without any context or briefing.

**Condition**
A rule in Conversational Flow that determines which branch to follow based on user response.

**Conversational Flow**
An agent type that uses a visual workflow builder for structured conversations.

## D

**Denoising**
Audio processing that removes background noise from caller audio for clearer speech recognition.

**Disposition**
The outcome category of a call (e.g., successful, unsuccessful, transferred).

## E

**Electron**
Smallest' voice-optimized Small Language Model (SLM) that handles reasoning and response generation with sub-500ms latency.

**Emotive Model**
A speech-to-speech AI model with emotional tone and natural expression (Beta).

**End Call**
The function that terminates a conversation based on defined conditions.

## G

**Global KB**
A Knowledge Base shared across multiple agents.

## I

**Inbound Call**
A call initiated by a customer to your agent's phone number.

## K

**Knowledge Base (KB)**
A repository of documents and information that agents can reference during conversations.

## L

**Latency**
The delay between when a user finishes speaking and when the agent starts responding.

**Lightning**
Smallest' Text-to-Speech model that synthesizes studio-quality voice at 44kHz with 175ms latency. Supports voice cloning and multiple languages.

**LLM (Large Language Model)**
The AI model that understands intent and generates responses.

**Local KB**
A Knowledge Base attached to and used by only one agent.

**Lock Agent**
A feature that prevents edits to an agent's configuration.

## N

**Node**
A single step in a Conversational Flow workflow (e.g., Prompt, Transfer, API Call, End).

## O

**Outbound Call**
A call initiated by your agent to a customer (via campaigns).

## P

**PII Redaction**
Automatic removal or masking of personally identifiable information from transcripts.

**Pulse**
Smallest' Speech-to-Text model with 64ms time-to-first-transcript latency. Supports 21 languages with automatic detection and industry-leading accuracy.

**Post-Call Metrics**
Analytics and data extracted from completed calls.

**Pre-Call API**
An API call that executes before the conversation starts.

**Post-Call API**
An API call that executes after the conversation ends.

## S

**SIP Trunk**
A connection between your own telephony provider or SBC and the platform, one resource per direction: an inbound trunk receives your calls, an outbound trunk places them.

**Single Prompt**
An agent type using one comprehensive prompt for flexible conversations.

**SLM (Small Language Model)**
Atoms' optimized models that deliver fast, efficient voice AI.

**Smart Turn Detection**
Intelligent handling of when the agent should start speaking.

**STT (Speech-to-Text)**
Technology that converts spoken audio into text.

## T

**Transfer Call**
Handing a conversation off to a human agent or another phone number. A transfer is a new outbound call and presents the agent's transfer number; without one, transfers on inbound calls are refused.

**TTS (Text-to-Speech)**
Technology that converts text responses into spoken audio.

**Turn Detection**
The system that determines when a speaker has finished and it's time to respond.

## V

**Variable**
Dynamic values that can be used in prompts (e.g., `{{customer_name}}`).

## W

**Warm Transfer**
A call transfer where the AI provides context to the receiving party before connecting.

**Webhook**
An HTTP callback that sends data when specific events occur.

**Whisper Message**
A message spoken only to the transfer recipient during warm transfer.

**Widget**
An embeddable voice interface for websites.

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## What's Next

#### [Getting Help](/voice-agents/resources/getting-help)

Contact support

#### [Key Terms](/voice-agents/resources/quick-reference)

Core concepts overview

> Definitions of key terms used in Atoms.