Family name מורדאק (Murdoch , מורדאק ) , across the world, is a common cognomen. The cognomen מורדאק is characteristic of Isle of Man, where it is quite a common surname, Australia, and New Zealand (explore the name in all countries). Measured by absolute frequency, the name is most common in the United Kingdom, the United States, and Australia. Much less frequently, מורדאק is the forename as well as the last name.