Liquidity pool
In short A liquidity pool is a smart contract holding two tokens that traders swap against directly, with the price set by the ratio of the reserves.
A liquidity pool is a smart contract that holds reserves of two assets, such as a small token and SOL, ETH, BNB, or a stablecoin. On a decentralized exchange, you trade against that pool instead of against another person's order. Anyone can create a pool for any token pair, which is why a brand-new token can be tradable within minutes of launching.
Most pools are automated market makers. In the classic design, the contract keeps the product of the two reserves constant. When you buy the token, you put the paired asset in and take the token out, so the token becomes scarcer in the pool and its price rises. Selling does the opposite. Liquidity providers deposit both sides, receive LP tokens that represent their share of the pool, and earn a cut of every swap fee.
Pool size matters more than most beginners expect. In a shallow pool, even a modest buy moves the price a lot, and selling later moves it back down just as hard. A quoted market cap is only price times supply and tells you nothing about whether holders can actually exit. The amount of paired asset sitting in the pool is the real limit on what everyone can sell.
Before buying a small token, look at the pool on a block explorer or a DEX analytics page. Compare its size with your trade, and check the price impact the swap interface shows before you confirm. Then find out who holds the LP tokens. If the creator holds them unlocked or can remove liquidity at will, they can drain the paired asset and leave you holding a worthless token, which is a rug pull. Locked or burned LP tokens reduce that risk but do not remove it. A healthy-looking pool can also sit behind a contract that blocks selling, so a pool existing is never proof that you can sell.