Volcanoes that have a record of eruptions can be classified as active or dormant.
On the other hand, volcanoes that have no record of eruption during the known history of existence is classified as inactive or extinct. The two are also basically different because, unlike extinct, an inactive volcano can be reactivated and once again erupt. To note, the Mount Pinatubo has no known eruption and considered to be inactive ever since until its explosive eruption in 1991.
