What is Absorption?

Absorption at its core means: passive limit orders soak up the other side's aggression, and price does not move despite the aggression. A classic description: lots of aggressive selling hits the bid, but the bid keeps getting refilled at the same price and price does not go lower. Delta becomes more and more negative, yet price stays put. Sometimes an iceberg order — an order that shows only a small part of its size and refills as it is consumed — sits behind this, but not necessarily.