Resistance
Definition
A price level where selling pressure is strong enough to prevent further advance.
Detailed Explanation
Resistance is a price level or zone where an uptrend can be expected to pause or reverse due to a concentration of supply. When price approaches resistance, sellers are more likely to sell and buyers are less willing to pay higher prices. Resistance forms at previous highs, round numbers, and moving averages. Multiple tests of resistance without breaking strengthen the level. When resistance breaks (with volume), it often becomes support.
Example
If TSLA repeatedly fails to break above $300 over several weeks, $300 is established resistance. Traders sell or short near $300 expecting rejection.