"liquid food," 1650s, from French soupe "soup, broth" (13c.), from Late Latin suppa "bread soaked in broth," from a Germanic source (cf. Middle Dutch sop "sop, broth"), from Proto-Germanic *sup-, from PIE *sub-, from root *seue- (2) "to take liquid" (see sup (v.2)).
Primordial soup is from a concept first expressed 1929 by J.B.S. Haldane. Soup to nuts "everything" is from 1910. Soup-kitchen, "public establishment supported by voluntary contributions, for preparing and serving soup to the poor at no cost" is attested from 1839. In Ireland, souper meant "Protestant clergyman seeking to make proselytes by dispensing soup in charity" (1854).
"increase the horsepower of an engine," 1921, probably from soup (n.) in slang sense of "narcotic injected into horses to make them run faster" (1911), influenced by supercharge (v.).
duck soup, in the soup, jerkwater, laughing soup, pea soup
liquid food prepared by cooking meat, poultry, fish, legumes, or vegetables with seasonings in water, stock, milk, or some other liquid medium. The cooking of soup is as ancient as the devising of vessels to hold liquid; before the development of pots that could withstand the direct heat of a fire, soups were cooked by dropping hot stones into the liquid. The long cooking of soup enabled nourishment to be drawn from meagre quantities of fish and meat too bony or tough to be otherwise utilized.