Tether (USDT) is a popular cryptocurrency that aims to provide stability and represent the value of traditional fiat currencies, primarily the United States dollar (USD). It is classified as a stablecoin because its value is designed to be pegged to the value of the underlying fiat currency.

Tether was launched in 2014 by a company called Tether Limited. It operates on various blockchain platforms, including Bitcoin, Ethereum, and others, using different technical standards such as Omni, ERC-20, and TRC-20. Tether is issued as tokens on these blockchains, representing a claim on the company's reserves of fiat currency.

The primary purpose of Tether is to facilitate the transfer of traditional fiat currencies in a digital form. It is widely used in the cryptocurrency ecosystem as a medium of exchange and a store of value. Traders and investors often use USDT as a way to hedge against price volatility in other cryptocurrencies since its value is relatively stable compared to many other digital assets.

Tether's stability is maintained by the company's claim to hold reserves of the underlying fiat currency at a 1:1 ratio to the issued tokens. However, the exact composition and auditing of these reserves have been a subject of controversy and speculation in the cryptocurrency community. Tether Limited has faced criticism for lacking full transparency and failing to provide regular audits that would verify the reserves.

It's important to note that as an AI language model, my knowledge is based on information available up until September 2021, and there may have been updates or changes to Tether since then. It's always a good idea to consult reliable sources or the latest information from official Tether channels for the most up-to-date and accurate details.