Cognomen Gniaz (Gniaz 
, Гняз 
) , all around the world, is a very rare surname. The last name Gniaz is habitual in Poland, where it is a very rare surname, Georgia, and Germany, where it is an extremely rare surname. Measured by absolute frequency, it is the most numerous in Poland, Germany, and the United Kingdom. More prevalently, Gniaz is the forename as well as the last name.