The story
From Chicago + style + pizza. From being a style of pizza that originated in Chicago, Illinois, USA.
Etymology from Wiktionary, CC BY-SA 4.0.
Chicago-style pizza
Today it means: A casserole-like deep-dish pizza with a characteristically high-edged crust on which the toppings are often layered upside down (first cheese and meat or vegetables, then tomato sauce). Full definition →