Last name 天乙 (Tianyi 
, 天乙 ) , globally, is a rare surname. The family name 天乙 is characteristic of Singapore, where it is a rare surname, Malaysia, where it is a very rare surname, and China. In absolute terms, it is commonest in China, Malaysia, and the United States. Much more prevalently, 天乙 is the forename as well as the last name.