Price levels where buying (support) or selling (resistance) pressure has historically caused the market to reverse or pause.
Support is a price floor where demand has previously exceeded supply; resistance is a ceiling where supply exceeded demand. When price approaches these levels, traders anticipate reactions and cluster orders there, making the levels self-reinforcing.
Support often becomes resistance after a break below, and vice versa. Identifying key levels requires combining price history, round numbers, and volume data. These levels are the foundation of most discretionary trading strategies.