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 flavour, 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 with dishes such as pasta can 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. Another variation is the pan sauce; this is made by adding an aromatic (such as chopped shallot) to a pan that has previously cooked meat, which has left hardened juices (called the fond) in the pan. After the aromatic has softened, a liquid (such as stock, wine, or water) is added to melt the fond in the bottom of the pan, a process called deglazing. An emulsifier, such as butter, can than be added to this quick sauce.
Sauces are an essential element in cuisines all over the world.
Sauces in French cuisine
Sauces in French cuisine date back to Medieval times. There were hundreds of sauces in the lore. In 'classic' 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. Carême's four mother sauces were:
· Allemande is based on stock with egg yolk & lemon juice
· Béchamel is based on flour and milk
· Espagnole is based on brown stock, beef etc.
· Velouté is based on a light broth, fish, chicken or veal.
In the early 20th century, the chef Auguste Escoffier updated the classification, replacing sauce Allemande with egg-based emulsions (Hollandaise and mayonnaise), and adding tomate. Escoffier's schema is still taught to chefs today:
· Béchamel
· Espagnole
· Hollandaise
· Tomato sauce
· Velouté

Most sauces commonly used in cooking are derivatives of one of the above mentioned mother sauces. Although these mother sauces are not commonly served in restaurants, many of their derivatives are. ie. Aioli, Béarnaise, Remoulade.

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. 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 alfredo, siciliana, pesto, pescatore and tomato sauces neapolitan sauce, pizzaiola, matriciana etc. mainly based on oil and garlic.
· Salsas ("sauces" in Spanish) such as guacamole, pico de gallo, 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.
· 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 are normally served with this sauce.)
· Chinese cuisine is known for prepared sauces based on fermented soy beans (soy sauce, black bean sauce, hoisin sauce) as well as many others such as chili sauces and oyster sauce. One of the more unusual (and popular) Chinese sauces is sweet and sour sauce, which contrasts two fundamental flavors not often found together in most cuisines.
· 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.
Asian prepared sauces are not thick as they do not contain thickening agents such as flour. The thickening occurs in the last minutes of cooking when thickeners like corn starch are added.