Finger Monkeys

Note that the smallest grouping that contains them all is the Simiiformes, the simians, which also contains the apes. Calling apes "monkeys" is considered scientifically incorrect as apes are distinctly defined as different from monkeys. Apes were included in earlier use of the term, predating modern classifications. Including some or all apes (other than humans) remained the common usage in the early 20th century and is still in colloquial use. Calling either a simian is correct.
Relationship with humans
The many species of monkey have varied relationships with humans. Some are kept as pets, others used as model organisms in laboratories or in space missions. They may be killed in monkey drives when they threatened agriculture, or used as service animals for the disabled.