Cognomen Nocturnus (Notturno 
, Nocturn 
, Noturno 
) , around the world, is a rare surname. The cognomen Nocturnus is habitual in Italy, where it is a rare surname, the Dominican Republic, and New Zealand, where it is a very rare surname. Measured by absolute frequency, it is commonest in Italy, the United States, and Brazil. Much less frequently, Nocturnus is the forename as well as the last name.