In cooking, a sauce is liquid or sometimes semi-solid food served on or used in preparing other foods. Sauces are not normally consumed by themselves; they add flavor, moisture, and visual appeal to another dish. Sauce is a French word taken from the Latin salsus, meaning salted. Sauces need a liquid component, but some sauces (for example, salsa or chutney) may contain more solid elements than liquid. Sauces are an essential element in cuisines all over the world.

Sauces may be ready made sauces, usually bought, such as soy sauce, or freshly prepared by the cook; such as Béchamel sauce, which is generally made just before serving. Sauces for salads are called salad dressing. Sauces made by deglazing a pan are called pan sauces.

A cook who specializes in making sauces is a "saucier".

Sauces in French cuisine

Sauces in French cuisine date back to the middle ages. There were hundreds of sauces in the culinary repertoire. In 'classical' French cooking (19th and 20th century until nouvelle cuisine), sauces were a major defining characteristic of French cuisine.

In the 19th century, the chef Antonin Carême classified sauces into four families, each of which was based on a mother sauce (Also called grandes sauces). Carême's four mother sauces were:

• Béchamel, based on milk, thickened with a white roux.
• Espagnole, based on brown stock (usually veal), thickened with a brown roux.
• Velouté, based on a white stock, thickened with a blonde roux.
• Allemande, based on velouté sauce, is thickened with egg yolks and heavy cream.

In the early 20th century, the chef Auguste Escoffier updated the classification, adding sauces such as tomato sauce, butter sauces and emulsified sauces such as Mayonnaise and Hollandaise.

Most sauces commonly used in classical cuisine are derivatives of one of the above mentioned mother sauces. Mother sauces are not commonly served as they are; instead they are augmented with additional ingredients to make derivative sauces. For example, Bechamel can be made into Mornay by the addition of Gruyère, and Espagnole becomes Bordelaise with the addition of reduced red wine and poached beef marrow.

Sauces in other cuisines

Sauces and condiments also play an important role in other cuisines:

• British cooking: Gravy is a traditional sauce used on roast dinner, which (traditionally) comprises roast potatoes, roast meat, boiled vegetables and optional Yorkshire puddings. The sole survivor of the medieval bread-thickened sauces, Bread sauce is one of the oldest sauces in British cooking, flavored with spices brought in during the first returns of the spice missions across the globe and thickened with dried bread. Apple sauce and mint sauce are also used on meat (pork and lamb respectively). Salad cream is sometimes used on salads. Ketchup and brown sauce are used on more fast-food type dishes. Strong English mustard (as well as French or American mustard) are also used on various foods, as is Worcestershire sauce. Custard is a popular dessert sauce. Some of these sauce traditions have been exported to ex-colonies such as the USA.
• Italian sauces include white sauces such as alfredo and besciamella and red sauces such as siciliana, pescatore, napolitan, pizzaiola, amatriciana, arrabbiata, ragù, and pesto sauces mainly based on oil and garlic.
• Salsas ("sauces" in Spanish) such as pico de gallo (salsa tricolor), salsa cocida, salsa verde, and salsa roja are a crucial part of many Latino cuisines in the Americas and Europe. Typical ingredients include tomato, onion, and spices; thicker sauces often contain avocado. Mexican cuisine uses a sauce based on chocolate and chillies known as Mole. Argentine cooking uses more Italian-derived sauces, such as tomato sauce, cream sauce, or pink sauce (the two mixed).
• Typical sauces used in Japanese cuisine are usually based on shōyu (soy sauce), miso or dashi. Ponzu, citrus-flavored soy sauce, and yakitori no tare, sweetened rich soy sauce, are examples of shoyu-based sauces. Miso-based sauces include gomamiso, miso with ground sesame, and amamiso, sweetened miso. (Note: in colloquial Japanese, the word "sauce" sometimes refers to Worcestershire sauce introduced in 19th century and largely arranged to Japanese tastes. Tonkatsu and yakisoba sauces are based on this sauce.)
• Chinese cuisine is known for prepared sauces based on fermented soy beans (soy sauce, doubanjiang, hoisin sauce, sweet noodle sauce) as well as many others such as chili sauces and oyster sauce. One of the more distinctive (and popular) Chinese sauces is sweet and sour sauce.
• Korean cuisine uses sauces such as doenjang, gochujang, samjang, and soy sauce.
• Southeast Asian cuisines, such as Thai and Vietnamese cuisine, often use fish sauce, made from fermented fish.
• Peruvian cuisine uses sauces based mostly in different varieties of ají combined with several ingredients most notably salsa huancaína based in fresh cheese and salsa de ocopa based on peanuts or nuts. It is said that each household in the country has its own secret salsa recipe.