Cognomen Seniak (Seniak 
, Сеняк 
) , all over the world, is a rare family name. The last name Seniak is habitual in Ukraine, where it is a rare surname, Armenia, and Russia, where it is a very rare surname. Measured by absolute frequency, the name is most common in Ukraine, Russia, and Germany. Very seldom, Seniak is the forename as well as the last name.