In English, name Bret means – A native of Brittany: (France) or Britain: (England). Derived from the surname Breton or Briton, Brett and Bret became popular first names after 19th-century US writer Bret Harte. Brett became very popular in Australia in the mid-20th century.. Other origins for name Bret include – English, French, Celtic, French, Celtic. Name Bret is a unisex name and can be used for a boy or girl name (male or female).