Monero (XMR) is a cryptocurrency which focuses on being untraceable and private. Its design differs from Bitcoin’s in a few key ways, but it should be understood as a cryptocurrency similar to Bitcoin – it can be used to buy and sell things, and can be exchanged for other coins or tokens.
So Monero XMR is a cryptocurrency focused on privacy and anonymity. Bitcoin is actually pseudonymous and BTC transactions are still traceable, but XMR transactions can be fully anonymized like physical cash. It is a fork of Bytecoin, the original privacy coin.