# Terms

> Short explanations of the most important words in Rasum – from chat and space to recovery key and key storage, presence, Matrix and Element.

Source: https://doc.rasum.chat/en/begriffe/

Here you find short explanations of words that appear in the app and in this help.

## Chat

A chat is a conversation in Rasum. A chat can be between two people or between many. You see all chats in the chat list under **"Chats"**. See [Chat list](https://doc.rasum.chat/en/chats/chatliste/).

## Direct chat

A direct chat is a chat between you and exactly one other person. Rasum only shows the green online dot on the profile picture in direct chats. In the chat list, you find direct chats with the **"People"** filter.

## Group

A group is a chat with several people. You create a group with **"Start chat"** → **"New room"**. Note: **"New room"** always creates a group. For a chat with just one person, search for the person in the **"Search for someone"** field instead. See [Start a new chat](https://doc.rasum.chat/en/chats/neuer-chat/).

## Space

A space brings several chats together under one roof, for example for a club or a family. You find spaces in the bar at the bottom under **"Spaces"**. See [Spaces](https://doc.rasum.chat/en/chats/spaces/).

## Username

The username is your unique address in Rasum. It has the form `@name:rasum.chat`. You choose it once when you create your account. Other people find you by this name. See [Profile](https://doc.rasum.chat/en/konto/profil/).

## Display name

The display name is the name others see next to your messages, for example "Anna". Unlike the username, you can change it at any time. See [Profile](https://doc.rasum.chat/en/konto/profil/).

## Server

The server is the computer that holds your account and that your messages pass through. For Rasum, this is always **rasum.chat**. You cannot choose a different server in the app.

## End-to-end encryption

End-to-end encryption means: a message is encrypted on your phone and only made readable again on the recipients' phones. In between, including on the server, it cannot be read. New chats in Rasum are encrypted. See [Encryption](https://doc.rasum.chat/en/sicherheit/verschluesselung/).

## Recovery key

The recovery key is a long string of characters. With it, a new device can read your old encrypted messages again. Rasum creates it automatically. Never give it to anyone – not even to support. See [Recovery key](https://doc.rasum.chat/en/sicherheit/wiederherstellungsschluessel/).

## Key storage

Key storage is the place where Rasum keeps your recovery key for you, encrypted. This lets you get back to your chats on a new device without typing anything.

**iPhone:** The key storage is your iCloud Keychain. The switch is called **"Save key in iCloud"**.

**Android:** The key storage is your Google account. The switch is called **"Store key in your Google account"**.

You find it under **"Settings"** → **"Encryption"**. See [Recovery key](https://doc.rasum.chat/en/sicherheit/wiederherstellungsschluessel/).

## Chat backup

The chat backup is an encrypted backup of your message keys on the server. It can only be opened with your recovery key. In Rasum, the chat backup cannot be turned off. Rasum sets it up automatically as soon as key storage is available; otherwise through **"Get recovery key"**. Do not confuse it with key storage: key storage keeps the recovery key, the chat backup keeps the keys of your messages.

## Confirm device

Confirming a device (also "verifying") means: you show Rasum that a new phone really belongs to you. Only then can it read your encrypted messages. You can do this with another signed-in device or with your recovery key. In the app, this step is called **"Confirm your digital identity"**. See [Confirm device](https://doc.rasum.chat/en/sicherheit/geraet-bestaetigen/).

## Digital identity

The digital identity is the encryption identifier of your account. Your devices and your contacts use it to recognise that messages really come from you. If it is reset, devices and contacts have to be confirmed again. See [Confirm device](https://doc.rasum.chat/en/sicherheit/geraet-bestaetigen/).

## Presence

Presence shows others whether you are active in Rasum right now. This includes the green online dot, read receipts and the "… is typing…" indicator. One switch controls all of it: **"Settings"** → **"Advanced settings"** → **"Share presence"**. See [Presence and read receipts](https://doc.rasum.chat/en/einstellungen/praesenz-und-lesebestaetigungen/).

## Read receipt

A read receipt shows who has read a message. In Rasum, small profile pictures of the readers appear below the message. There is no double check mark. See [Message status](https://doc.rasum.chat/en/nachrichten/status/).

## Mention

A mention is a name with @ in a message, for example @Anna. The mentioned person gets a targeted notification. In the chat list, the @ symbol shows new mentions. See [Write a message](https://doc.rasum.chat/en/nachrichten/schreiben/).

## Pin

Pinning means: a message is attached to the top of the chat so that everyone can find it quickly. The opposite is called **"Unpin"** in the app. See [Edit, delete and more](https://doc.rasum.chat/en/nachrichten/bearbeiten-loeschen/).

## Matrix

Matrix is an open standard for chats and calls on the internet. Rasum uses Matrix in the background. You rarely see it, for example in chat addresses like `#name:rasum.chat`.

## Element

Element is an open-source messenger app that Rasum is built on. That is why "Element" still appears in a few places in the app, for example with some notification sounds or in some notices about calls. You are still using Rasum and the server rasum.chat.