Put wall
The strike that holds more put gamma than any other strike nearby. Traders watch it as a level where hedging flows may change on a move lower.
A put wall is the put-side counterpart of a call wall: the strike where put open interest and gamma combine into more put gamma exposure than at any other strike nearby. GEX models usually assume dealers are short those puts, so the strike marks where their hedging needs are concentrated if the price falls toward it.
Like a call wall, it is a model output that depends on the assumed dealer side, and it can move or vanish when the options expire. On a net GEX chart such as CaymanBot's, the deepest negative bars play the put-wall role.
Illustrative example (hypothetical numbers, not a real trade): the 95 strike carries 30,000 puts with a gamma of 0.03, more than any nearby strike. Its share-equivalent gamma is 30,000 × 0.03 × 100 = 90,000 shares per $1 move, which makes 95 the put wall.