Stablecoins are digital assets whose value is pegged to a dollar. I.e. the price of a stablecoin is aimed at always being $1. The price of a stablecoin is kept fixed either via holding reserves of actual dollars or via algorithmic mechanisms of buying and selling a reference asset.
Our main stablecoin is USDC (USD Coin). For every 1 USDC in supply, $1 USD is kept in reserve.