Jack Tar (also Jacktar, Jack-tar or Tar) was a common English term originally used to refer to seamen of the Merchant or Royal Navy, particularly during the period of the British Empire. By World War I the term was used as a nickname for those in the U.S. Navy. Both members of the public, and seafarers themselves, made use of the name in identifying those who went to sea. It was not used as an offensive term and sailors were happy to use the term to label themselves.

Jack Tar (also Jacktar, Jack-tar or Tar) was a common English term originally used to refer to seamen of the Merchant or Royal Navy, particularly during the period of the British Empire. By World War I the term was used as a nickname for those in the U.S. Navy. Both members of the public, and seafarers themselves, made use of the name in identifying those who went to sea. It was not used as an offensive term and sailors were happy to use the term to label themselves.