USDT (Tether) is a type of stablecoin, which is a cryptocurrency designed to maintain a stable value by pegging it to a reserve asset, typically the U.S. dollar. The value of 1 USDT is typically maintained at 1 USD, making it a popular choice for traders to move in and out of other cryptocurrencies while minimizing price volatility. Tether is commonly used on cryptocurrency exchanges and for transactions where stability is needed.