A telegram can refer to two different things: a communication sent over a telegraph, or a cloud-based instant messaging service called Telegram Messenger).

• Telegraph Telegram: A telegram is a written message transmitted using an electric device, carried along wires, and delivered by hand or teleprinter. Telegrams were widely used in the past because private telephones were not common, but they are now rare in most parts of the world.

• Telegram Messenger: Telegram Messenger is an encrypted, cloud-based, cross-platform instant messaging service that allows users to exchange messages, share media and files, live location, and hold private and group voice or video calls, as well as public livestreams). It is available for Android, iOS, Windows, macOS, Linux, and web browsers). Telegram provides end-to-end encryption in voice and video calls, and in optional private chats, which Telegram calls Secret Chats). Telegram also has social networking features, allowing users to post stories, create large public groups with up to 200,000 members, or share one-way updates to unlimited audiences in so-called channels). The service also provides an open API for the creation of custom bots which can perform various tasks, integrate other services into Telegram chats, or work as mini apps). Telegrams default messages are cloud-based and can be accessed on any of the users connected devices). Users can share photos, videos, audio messages, and other files (up to 2 gigabytes per file) ). Users can send messages to other users individually or in groups of up to 200,000 members). Sent messages can be edited up to 48 hours after they have been sent and can be deleted at any time on both sides). Telegram uses a custom-built symmetric encryption scheme called MTProto).

In summary, a telegram can refer to a communication sent over a telegraph or a cloud-based instant messaging service called Telegram Messenger.