This guide lists terms that are important to understand,
but are not necessarily associated with any resource.

## Active

At any given moment during a conversation,
one of the following is true:

- One and only one playbook is *active*.
- One and only one page and the associated flow are *active*.

## Agent, human agent, live agent, virtual agent, bot, and chat bot

In this documentation, without context, *agent* refers to the virtual agent.
When it is important to provide a distinction,
a contact center may have both *human agents*
(also called *live agents* ) and *virtual agents*.

*Virtual agent* , *bot* , and *chat bot* are synonymous,
however, *chat bot* may imply a text-only interface in some contexts.

## Audio input, speech recognition, and speech-to-text

End-user input as an audio file or
streamed audio sent at runtime to the agent API.
Audio containing speech is transcribed by *speech recognition* (*speech-to-text*)
and the transcripts are processed.

## Audio output, speech synthesis, and text-to-speech

Agent output as an audio file or
streamed audio sent at runtime to the agent's client.
Agent text responses use *speech synthesis* (*text-to-speech*)
to convert text to audio.

## Back-end and front-end

*Back-end* is the part of your system that is responsible for business logic.
This is in contrast with the *front-end*,
which provides a user interface.

## Contact center

Software that allows companies to automate communication between their customers
(referred to as end-users) and human or virtual agents.

## Contact center operator

A person operating a contact center by using a contact center software solution.

## Conversation and session

End-user interaction with a virtual or human agent.
*Conversation* is synonymous with *session*.

## Conversation turn, end-user input, and user query

A *conversation turn* is one interaction between an
end-user and the virtual agent.
The end-user provides an input
(also called user query)
and the agent provides a response.

## Runtime and design-time

When using the console or API to build an agent,
this is a *design-time* activity.
When the agent is in a conversation with an end-user,
this is a *runtime* activity.

## User, end-user, and developer user

There are two types of users:

- *End-users*: People who have conversations with the agent.
- *Developer users*: Developers who build agents.

In this documentation,
without context,
*user* and *end-user* are equivalent.