Cognomen ויאנו (Vianu 
, ויאנו 
) , worldwide, is a rare family name. The last name ויאנו is characteristic of Romania, where it is a rare surname, Israel, where it is a very rare surname, and Nigeria. Measured by absolute frequency, it is commonest in Romania, Nigeria, and the United States. Very seldom, ויאנו is the forename as well as the last name.