An elephant has one stomach chamber.
Unlike cattle, sheep, and other ruminants, elephants are monogastric herbivores: their stomach is a single, relatively simple chamber. Their plant-based diet is processed farther along the digestive tract rather than in a four-part fore-stomach.
The major fermentation work happens in the hindgut, especially the caecum and colon, where microbes help break down cellulose and other plant fibres. This arrangement lets elephants consume large amounts of vegetation, but it is comparatively inefficient: much of what they eat passes through only partly digested.
The common mix-up comes from confusing elephants with ruminants. Cows have a four-compartment stomach, but elephants do not chew cud and do not have rumen, reticulum, omasum, and abomasum. An elephant’s long intestines—not multiple stomach chambers—handle much of the plant digestion.