Orangutans (also spelled orang-utan, orangutang, or orang-utang) are great apes native to Indonesia and Malaysia. They are found in the rainforests of Borneo and Sumatra, but during the Pleistocene they ranged throughout Southeast Asia and South China.

The name "orangutan" (also written orang-utan, orang utan, orangutang, and ourang-outang) is derived from the Malay words orang, meaning "man", and hutan, meaning "forest". The locals originally used the name to refer to actual forest-dwelling people.

The word was first attested in English in 1691 in the form orang-outang, and variants ending with -ng are found in many languages. This spelling (and pronunciation) has remained in use in English up to the present but has come to be regarded as incorrect. The loss of "h" in Utan and the shift from -ng to -n has been taken to suggest the term entered English through Portuguese.

Malay, the term was first attested in 1840, not as an indigenous name but referring to how the English called the animal. The word 'orangutan' in Malay and Indonesian today was borrowed from English or Dutch in the 20th century—explaining why the initial 'h' of 'hutan' is also missing.

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