Soup or stew?
What is the difference between soup and stew? On the most basic level there is no absolute difference. Like ancient pottage, both soup and stew descend from economical, easy, healthy, forgiving, and locally sourced family feeds. Throughout time, these two interrelated menu items converge and diverge. Modern American cultural context does, however, separate soup from stew quite simply. The test is not in the ingredients or method, but which course it is served. Soup is starter/accompaniment; stew is main course.
Soup, in some contexts, variously became regarded as haute cuisine (consomme, vichyssoise), healthful restoratifs (18th century French Restaurants & Jewish grandmother chicken soup), and economical family fare (commercial vegetable beef, tomato). Soup can be served as first course (classic menu), lunch (paired with sandwich or salad) and dessert (fruit soup). It can be served hot (most) or cold (gazpacho, cucumber). Either way, the stock reigns supreme.
Stew is generally appreciated in larger chunks as main course, always served warm. Slow cooking renders tough cuts of meat delicious. The fact “stew” was a verb before it was a noun means much. Deliberate slow cooking with minimal moisture produces amazing results. Stew is generally regarded as community feed ( Brunswick Stew, Kentucky Burgoo & Booya) or family fare; not eligible for haute cuisine.
The best way to compare definitions of two terms is take them from the same source. It is interesting to note Escoffier does not attempt to define the differences. If you’re examining the differences within a specific culture/cuisine/period context, compare soup and stew recipes offered in cookbooks serving your target period. Menus confirm meal placement.
 The Master Dictionary of Food & Cookery, Henry Smith [Philosophical Library:New York]
“Soup as a food consists of water in which meat, fish, poultry, game, vegetables or even fruits are stewed, to extract all the food value with the least possible loss of vitamins and flavour. Cereals and thickening agents are sometimes added to give body.”—(p. 225)
“Stew…is nothing more or less than simmering foods in the smallest possible quantity of liquid. The meat, poultry or game and liquid are served together as a ‘stew,’…Stewing has many advantages from the nutritive and economic standpoints.”—(p. 230)
 The New Food Lover’s Companion, Sharon Tyler Herbst [Barrons Eduational Series:New York] , 3rd edition
“Soup. Theoretically, a soup can be made in any combination or vegetables, meat or fish cooked in a liquid. it may be thick (like Gumbo), thin (such as a Consomme), smooth (like a Bisque) or chunky (Chowder or Bouillabaisse). Though most soups are hot, some like Vichyssoise and Fruit Soups are served cold…The can be served as a first course or as a meal, in which case they’re usually accompanied by a sandwich or salad.”—(p. 581)
“Stew. Any dish that is prepared by stewing. The term is most often applied to dishes that combine meat, vegetables and a thick soup-like broth resulting from a combination of the stewing liquid and the natural juices of the food being processed.”—(p. 596)
 Encyclopedia of Food Culture, Solomon H. Katz, editor-in-Chief [Thomson Gale:New York] Volume 3
“Soup. A soup is a broth that is infused with flavor. It may be think and crystal clear like a consomme, voluptuously smooth and creamy like a creamed soup, or so chunky with meat, fish, grains, and/or vegetables it is just this side of stew. A soup may be the first of several courses, intended just to whet the appetite; it may be one of many dishes served at the same time; or it may be a hearty meal in a bowl. The bottom line is that in order to be soup, it must be enough of a liquid preparation that eventually one gets around to sipping it, or eating it with a spoon.”—(p. 297)
“Stew. A stew had been described as an assortment of foods cooked in liquid within a container with a lid. Stews are usually made from several ingredients and may be named for the most important of these, for example, beef stew; for its point of origin, for its point of origin, as in Irish stew; or for the pot in which it is cooked, as in Rumanian ghivexi, named for the Turkish guvec, an earthenware pot in which the stew is cooked. The word “stew” is said to have come from the old French word estuir, meaning to enclose.”…Stews are commonly regarded as ‘comfort’ foods, everyday dishes served to family or close friends in an intimate setting, rather than as fare in more public settings or at special occasions.”—(p. 341-342)