The appropriate scientific classification for any monkey is either "simian" or "primate." However, there are over 260 species of monkeys, not including hominids, that belong to the infraorder Simiiformes.
Monkeys make up a broad collection of animals including both arboreal and terrestrial non-human primates, each with its own specific taxonomy, or scientific name. This collection is broadly separated into either Old World monkeys, which are found in Asia and Africa, and New World monkeys found in the Americas. These include baboons, marmosets and spider monkeys. The term "monkey" is also commonly used interchangeably with "ape," which commonly refers to the great apes; that is, chimpanzees, gorillas and orangutans.