"Oreum" refers to a tiny volcanic zone that contains a volcanic cone, omnipresent at Jeju Island, excluding Paekrokdam at the peak of Hallasan. It is a typical Jeju dialect that indicates an independent volcanic zone, made of ejecta or a parasite volcano.

The origin of the word "Oreum" is traced to a noun, made from the verb "mount," and it is thought to imply a small hill or slope that one can easily climb.

Jeju Island is a volcanic one, resulting from a series of volcanic explosions that have occurred not so long ago. The time period for Jeju Island's geographical origin is presumed to range from 500,000 to 2 million years ago, a relatively recent event, considering the 4.6- billion- year earth history.

A parasite volcano is a small volcanic zone and is widespread around the Hallasan ridges and volcanic piedmont areas, the mountain being located at the heart of Jeju Island.

Most of the Oreums, Jeju Island's unique parasite volcanos, were formed out of small sized sporadic volcanic explosions at the Halla Mountain piedmont areas a few tens and thousands, or even hundreds and thousands of years ago.