Soup is a primarily liquid food, generally served warm or hot (but may be cool or cold), that is made by combining ingredients of meat or vegetables with stock, milk, or water. Hot soups are additionally characterized by boiling solid ingredients in liquids in a pot until the flavors are extracted, forming a broth. Soups are similar to stews, and in some cases there may not be a clear distinction between the two; however, soups generally have more liquid (broth) than stews.
In traditional French cuisine, soups are classified into two main groups: clear soups and thick soups. The established French classifications of clear soups are bouillon and consommé. Thick soups are classified depending upon the type of thickening agent used: purées are vegetable soups thickened with starch; bisques are made from puréed shellfish or vegetables thickened with cream; cream soups may be thickened with béchamel sauce; and veloutés are thickened with eggs, butter, and cream. Other ingredients commonly used to thicken soups and broths include rice, lentils, flour, and grains; many popular soups also include pumpkin, carrots, potatoes, pig's trotters and bird's nests.
Other types of soup include fruit soups, dessert soups, pulse soups like split pea, cold soups and other styles.
The earliest evidence for soup in human culinary practice dates to the Upper Palaeolithic period when thermally altered rocks became commonplace in the archaeological record. Small boiling pits are present on the Gravettian site Pavlov VI. Cobbles were heated on the hearth and then placed into the water to bring it to boil. However, the antiquity of soup is highly contested. Based on ethnographic evidence, some archaeologists conjecture that early humans employed hides and watertight baskets to boil water.
The word soup comes from French soupe ("soup", "broth"), which comes through Vulgar Latin suppa ("bread soaked in broth") from a Germanic source, from which also comes the word "sop", a piece of bread used to soak up soup or a thick stew.