Plain meaning
Start with the shortest useful explanation before going deeper.
A token pegged to a stable asset, typically the US dollar. Major stablecoins on Solana include USDC (Circle, natively minted), USDT (Tether), and UXD (algorithmic). Stablecoins are critical DeFi primitives used as trading pairs, lending collateral, and yield farming. USDC on Solana uses the SPL Token program with freeze authority retained by Circle.