Jarl, a Scandinavian title used in both historical and modern contexts, refers to a ruler or lord. The term has several synonyms which are commonly used interchangeably, including chieftain, warlord, earl, and thane. A chieftain is someone who controls a group or clan, while a warlord is a military commander who holds significant power. An earl is a nobleman who holds a hereditary title in the British system, while a thane was a noble in medieval Scotland and northern England. The term "Jarl" is often associated with Viking Age Scandinavia and was both a title and a rank of nobility, much like the English title of Earl.