# Glossary

Alphabetical list of terms used throughout the documentation and in the SDK.

##### Channel

Where conversations take place between two or more chat users. They contain a list of messages and have a list of member users that are participating in the conversation. A channel is identified by its `type` and `id`.

##### Chat Client

Low-level wrapper around the Stream Chat API. Contains basic model objects, such as `User`, `Channel`, or `Message`. Allows operations like user authentication, event handling, channel creation and message sending. Represented by the `ChatClient` class.

##### Chat State

Data that can be observed in a reactive way through `StateFlows`, like loading state, list of available channels, messages, members and more. Provided by the low-level client as a plugin and used in both of our UI component libraries. It can also be used directly, with a custom UI layer on top.

##### Event

Mechanism that allows the client to react to changes in the chat. Events are triggered under various circumstances, such as when a new message was sent, a user avatar update, a new reaction, or a member joined the channel. Events are only received when the client is connected to the socket and the application is in the foreground.

##### Message

Single communication inside a channel. Besides typical communication-related fields like text, created date or message sender, it also contains other useful components like attachments and reactions.

##### Offline Support

Refers to the implementation of the `OfflinePlugin`, a persistence layer designed to improve the user experience on mobile devices that may not have a network connection. It offers several advantages, like reduced initial load times, the ability to view cached channels and messages, and sending messages and reactions while offline.

##### Theming

Process of customizing aspects of the UI, such as font, text color, background, text style, drawables and more. For our XML-based UI Components it can be done via XML View attributes, by using the `TransformStyle` object or by using themes. For our Compose UI Components it can be done using `ChatTheme`.

##### UI Component

Pre-build `View` or `Composable` offered by Stream Chat in the UI Components or Compose UI Components libraries. Built on top of the low-level client.

##### User

A person who uses chat and can perform chat operations like viewing channels or sending messages. Represented by the `User` model, with a unique ID and defined set of permissions.


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This page was last updated at 2026-04-21T07:55:27.213Z.

For the most recent version of this documentation, visit [https://getstream.io/chat/docs/sdk/android/v6/resources/glossary/](https://getstream.io/chat/docs/sdk/android/v6/resources/glossary/).