Dealer gamma — options dealers must buy/sell the underlying to stay hedged. Net $gamma per strike measures how much, and where.
Short gamma (negative) — dealers sell dips / buy rips → they AMPLIFY moves (trendy, fast). Long gamma (positive) → they DAMPEN/pin moves (calm, range-bound).
Zero-gamma flip — the price where net gamma crosses zero; dealer behaviour inverts there. Above/below the flip changes the regime's push.
Call wall / put wall — the biggest positive-gamma strike above spot (resistance) and negative-gamma strike below (support). Price tends to gravitate to / stall at these.
Magnet — the dominant-gamma strike near spot; the level hedging pulls toward. Above spot = ↑ pull, below = ↓ pull.