Cognomen Ool (Ool 
, Оол 
, 올) , around the globe, is quite a rare last name. The family name Ool is habitual in Estonia, where it is quite a rare surname, Netherlands, and Taiwan, where it is a rare surname. In absolute terms, the name is most common in Egypt, Netherlands, and Saudi Arabia. Much less frequently, Ool is the forename as well as the last name.