dYdX is the governance token of the dYdX platform that can be used to earn rewards, participate in staking pools, and receive discounts on fees incurred on the dYdX exchange.

dYdX is a decentralized exchange platform built on Ethereum that leverages a combination of on-chain and off-chain processes to facilitate trading using a non-custodial order book model. Unlike other DEXs that use an AMM model, dYdX is able to offer an institutional-grade, low slippage trading experience to users by utilizing StarkWare’s StarkEx Layer 2 scalability engine to facilitate near-instant trade settlement, lower minimum trade sizes,  and reduced Gas/trading fees. Asides from spot trading, dYdX also offers margin trading, lending and borrowing, and perpetual contracts.

More info here https://dydx.exchange/