Last name Brénainn (Brendan 
, Breandán , Brandán 
) , in the world, is quite a common cognomen. The cognomen Brénainn is habitual in Malaysia, where it is quite a rare surname, Ireland, and Nigeria. Measured by absolute frequency, this name is the most popular in Nigeria, Malaysia, and Tanzania. More frequently, Brénainn is the forename as well as the last name.