A steak is a cut of meat sliced across muscle fibers, sometimes including a bone. It is normally grilled or fried, and can be diced or cooked in sauce.

Steaks are most commonly cut from cattle (beefsteak), but can also be cut from bison, buffalo, camel, goat, horse, kangaroo, sheep, ostrich, pigs, turkey, and deer, as well as various types of fish, especially salmon and large fish such as swordfish, shark, and marlin. Some cured meat, such as gammon, is commonly served as steak. Some cuts are categorized as steaks not because they are cut across the muscle fibers, but because they are relatively thin and cooked over a grill, such as skirt steak and flank steak.

Grilled portobello mushroom may be called mushroom steak, and similarly for other vegetarian dishes. Imitation steak is a food product that is formed into a steak shape from various pieces of meat. Grilled fruits such as watermelon have been used as vegetarian steak alternatives.

The word steak was written steke in Middle English, and comes from the mid-15th century Scandinavian word steik, related to the Old Norse steikja 'to roast on a stake', and so is related to the word stick or stake. The primary definition is "a thick slice of meat cut for roasting or grilling or frying, sometimes used in a pie or pudding; especially a piece cut from the hind-quarters of the animal". Fish suitable for cutting steaks from might be called "steak fish". An early written usage of the word "stekys" comes from a 15th-century cookbook, and makes reference to both beef or venison steaks.

Countries with enough suitable land for grazing animals, in particular cattle, have a history of production and culinary use of steak. Such countries include Argentina, Ireland, New Zealand, Australia, South Africa, the United States, and the United Kingdom.

Argentina has one of the largest consumptions of beef per capita worldwide, and much of it is grilled steak. Beef steak consumption is described as part of the "Argentine national identity". Portion sizes of steak dishes in Argentine restaurants tend to be large, with steaks weighing over 454 grams (1 lb) being commonplace. Asado, considered a national dish, often includes steak.

The "Steak of Origin" competition has been run for a decade on behalf of the Beef+Lamb Corporation of New Zealand. It "aims to find the most tender and tasty sirloin steak" in the country. Criteria for judging claims to include tenderness, pH, marbling and percentage cooking loss", but while these data are collected for each entrant steak, only the shear force (correlated to perceived tenderness) determines qualification to a tasting panel, at which objective taste from a panel determines the winner. The pH is used solely to disqualify entrants and neither the marbling or the cooking loss have any effect on the outcome of the competition at any stage.

Beef steaks are commonly grilled or fried. Grilled beef steaks can be cooked at different temperatures, or for different lengths of time; the resulting cooked steak ranges from blue (very rare) to overdone. The outside is usually seared for flavor, while the inside is cooked to suit the diner's preference. Steaks cooked well done are usually cooked throughout the entire cut of meat. For example, a beefsteak cooked well done will not have any pinkness in the middle when sliced. Uncooked beef steak can be served raw, such as in steak tartare.