Also Chicken and andouille gumbo, Seafood gumbo, Gumbo z'herbes
A thick, dark stew-soup built on a roux and the holy trinity, with meat or seafood, served over rice.
What makes it gumbo
A roux, often cooked very dark.
The holy trinity, cooked down.
Thickened by roux, okra or filé — or a combination.
Served over white rice.
Where it comes from
Its roots are West African, French and Choctaw at once, and the name shows it: it's usually traced to a West African word for okra, though some point to a Choctaw word for filé. Okra, filé and roux are its three thickeners, and each cook has an opinion about which belongs.
Creole gumbo, in the city, tends to have seafood and sometimes tomato; Cajun gumbo, in the country, a very dark roux with chicken and smoked sausage. It's served over rice, often with potato salad on the side — or in it.
How it varies
Chicken and andouille
The Cajun standard, with a dark roux and no tomato.
Seafood gumbo
Prawns, crab and oysters, often with okra.
Gumbo z'herbes
Green gumbo of many kinds of greens, traditionally made for Holy Thursday.