The price floors where buyers step in (support) and ceilings where sellers step in (resistance).
Support is a level where falling price has repeatedly found buyers and bounced; resistance is a level where rising price has repeatedly met sellers and stalled. They are zones, not exact lines.
Price tends to react at these levels — bouncing, stalling, or breaking through. A clean break of resistance can turn it into new support (and vice-versa), called a role reversal.
Mark the prices where the chart has turned more than once. The more touches and the more recent, the more meaningful the level; round numbers and prior swing highs/lows are common ones.
Levels are approximate and get broken. False breaks are common, so wait for a reaction or close beyond the level rather than assuming it will hold or break cleanly.
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