$BTC Bitcoin — the first and most popular cryptocurrency in the world. Cryptocurrencies, including Bitcoin, operate on the basis of blockchain — a technology for encrypting and storing data, distributed across a multitude of computers connected in a common network. 1

ru.investing.com: Bitcoin (Bitcoin) is a type of digital cryptocurrency that allows the creation of a modern asset through transactions between independent nodes, mining, and other technologies. 2

binance.com: Bitcoin (BTC) is one of the most popular cryptocurrencies on the market, first introduced in 2009 by Satoshi Nakamoto. There is no physical token for BTC, so Bitcoin functions as a digital currency. 3

journal.tinkoff.ru: Bitcoin is digital money that does not physically exist. New units of Bitcoin emerge as computers in the payment network serve the needs of that same network. 4

ru.wikipedia.org: Bitcoin is a peer-to-peer payment system that uses the same-named unit for accounting transactions. Cryptographic methods are used to ensure the functioning and protection of the system, and all information about transactions between addresses in the system is publicly available.