Cognomen Uên (Wales 
, Uên) , all over the world, is a common last name. The cognomen Uên is habitual in Isle of Man, where it is quite a common surname, the United Kingdom, where it is quite a rare surname, and Australia. In absolute terms, it is commonest in the United States, the United Kingdom, and Tanzania. Much less frequently, Uên is the forename as well as the last name.