Family name Флак (Flak 
, Flaco 
, Flac 
) , in all the world, is quite a common last name. The last name Флак is characteristic of Panama, where it is quite a rare surname, Poland, and Guinea-Bissau. Measured by absolute frequency, it is the most numerous in Poland, the United States, and Panama. Also, Флак is the forename as well as the last name.