Resistance
A price area where rising prices have stalled and turned back down before.
Resistance is the opposite of support. It is a price area where a rising market has stalled and turned lower more than once, because sellers showed up around that price.
Like support, resistance is a zone, not a perfect line. Price may poke above it for a moment and still fall back. A clean break above resistance, with price holding there, is sometimes called a breakout. A move above that quickly fails is called a fakeout.
After a real breakout, old resistance often becomes new support. Learning to tell a breakout from a fakeout is one of the first chart-reading skills worth practicing.
Example: a stock climbs to about $80 twice and drops back both times. The $79 to $81 area is resistance until price closes and holds above it.
New to all of this? Start learning trading from zero.
Educational definition. Not financial advice; no real-money execution.