In cooking, a sauce is liquid or sometimes semi-solid food served on or used in preparing other foods. Sauces are not 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 may be prepared sauces, such as soy sauce, which are usually bought, not made, by the cook; or cooked sauces, such as Béchamel sauce, which are generally made just before serving. Sauces for salads are called salad dressing. Sauces made by deglazing a pan are called pan sauces.

A person who specializes in making sauces is often referred to as a "saucier", a French term borrowed for its situational usefulness. Sauces are an essential element in cuisines all over the world. Some famous sauciers include Julia Child, Benjamin Christie, Yutaka Ishinabe, and François Pierre La Varenne.

Sauces in French cuisine

Sauces in French cuisine date back to Medieval times. 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 grand sauces). Carême's four mother sauces were:

• Allemande, based on white stock, thickened with egg yolk.
• Béchamel, based on milk, thickened with roux.
• Espagnole, based on brown stock (usually veal), thickened with roux.
• Velouté, based on a white stock, thickened with roux.

In the early 20th century, the chef Auguste Escoffier updated the classification, adding new 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-is; 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. 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 balsamella 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 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.
• 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.