A perpetual contract in cryptocurrency trading is a type of derivative product that enables traders to speculate on the price movements of cryptocurrencies without actually owning the underlying assets. Unlike traditional futures contracts that have expiry dates, perpetual contracts do not have a set expiration date, allowing traders to hold positions indefinitely. These contracts use a funding mechanism to ensure that the contract price closely tracks the spot price of the cryptocurrency, making them popular among traders for their flexibility and potential for profit.