Worldwide, Oin (Oin 
, 오인, โออิน ) is a rare epicene forename. The given name Oin is habitual in Romania, where it is a rare boy's name, Indonesia, where it is a very rare epicene name, and Nigeria, where it is an extremely rare gender-neutral name. Measured by absolute frequency, the name is most common in Indonesia, Romania, and India. More prevalently, Oin is the last name as well as the forename.