Barbecue rub (or dry rub) is a blend of dry spices and herbs, such as paprika, chili powder, garlic powder, onion powder, brown sugar, and salt, rubbed onto meat before smoking, grilling, or roasting to season the surface and help form a flavorful crust, or "bark."
The style developed in Southern American barbecue, where pit cooks built their own blends from regionally available spices. A rub differs from a marinade or sauce in that it contains no liquid: it's applied dry, sometimes hours before cooking, while sauces and marinades are wet and are brushed on or soaked in.
Similar dry seasoning blends appear in Caribbean, Latin American, and Asian cooking, adapted with local spices such as allspice, cumin, or five-spice.
A typical rub balances sweetness (brown sugar or molasses) with savory, smoky notes (paprika, chili powder, garlic, onion), and is used on meat, poultry, seafood, and vegetables alike.