The Celts (/ˈkɛlts/, occasionally /ˈsɛlts/, see pronunciation of Celtic) or Kelts were an ethnolinguistic group of tribal societies in Iron Age and Medieval Europe who spoke Celtic languages and had a similar culture, although the relationship between the ethnic, linguistic and cultural elements remains uncertain and controversial. The Celtic nations are territories in Northern and Western Europe whose own Celtic languages and/or cultural traits have survived.
The term “nation” is used in its original sense to mean a people who share a common identity and culture and are identified with a traditional territory. It is not synonymous with “sovereign state”.
The six territories recognised as Celtic nations are Brittany (Breizh), Cornwall (Kernow), Ireland (Éire), the Isle of Man (Mannin), Scotland (Alba), and Wales (Cymru). Each of these regions has a Celtic language that is either still spoken or was spoken into modern times. Territories in north-western Iberia—particularly Galicia and Asturias; sometimes referred to as Gallaecia, which includes North and North-Central Portugal —are sometimes included due to their culture and history. Unlike the others, however, no Celtic language has been spoken there in modern times. Before the expansions of Ancient Rome and the Germanic tribes, a significant part of Europe was Celtic.