USDT- Coins

A stablecoin is a class of cryptocurrencies that attempt to offer price stability and are backed by a reserve asset. Stablecoins have gained traction as they attempt to offer the best of both worlds—the instant processing and security or privacy of payments of cryptocurrencies, and the volatility-free stable valuations of fiat currencies.

USDT Coins like Tether (USDT) is a stablecoin, or a type of cryptocurrency which aims to keep cryptocurrency valuations stable. Tether is used by crypto investors who want to avoid the extreme volatility of other cryptocurrencies while keeping value within the crypto market.

Many crypto coins can be converted or traded using a USDT pair, meaning you can trade the coin for its equivalent in USDT tokens- for its exact U.S. dollar value.

Source: Investopedia