Tether (USDT) is a cryptocurrency that is anchored to the US dollar. It was launched in 2014, and it is designed to provide the benefits of cryptocurrency, like fast and borderless transactions, with the stability of fiat money. One USDT is equal to one US dollar, which means that its value is always maintained at the same level as the US dollar.

The main application of Tether is as a stablecoin for traders and investors who want to avoid the volatility of other cryptocurrencies. For example, if a trader wants to take a position in Bitcoin but is worried about the price fluctuations, they can convert their Bitcoin into Tether, which will keep its value fixed to the US dollar. This way, they can avoid the risk of losing money if Bitcoin falls in price.

Tether can also be used as a means of payment, much like other cryptocurrencies. Its stable value makes it an attractive option for merchants who want to accept cryptocurrency payments but don't want to take on the risk of value fluctuations. Some merchants also appreciate Tether's low transaction fees and fast confirmation times compared to traditional payment methods like credit cards.

Overall, Tether has become a popular cryptocurrency because of its stability, low volatility, and widespread adoption. It is used by traders, investors, merchants, and individuals who want to hold a digital asset that is immune to market fluctuations.