Other forms: clans
A clan is a group of families claiming descent from a common ancestor. A Highland clan, the clan chief, clan tartan.
In Scotland the clan system organised land, loyalty and warfare until it was broken after 1746, and the tartans people now associate with clans were largely standardised in the nineteenth century. Clan systems exist in many societies. Informally, the clan means somebody's extended family: the whole clan turned up. Note clannish, which means loyal to your own group and suspicious of outsiders, and is not a compliment.
1nounclanA group of families claiming a common ancestor.
“Every member of the clan claimed to be descended from the same Viking chief.”
2nounextendedSomebody's extended family.
“The whole clan came to Grandma's birthday, including cousins from Australia.”
clan is a family group.
Scottish Gaelic clann means children or offspring, and it comes from Latin planta, a shoot or plant — borrowed into Irish with p becoming c. A clan is literally a family's shoots.
Irish
clann
English, today
clan
Borrowed from Irish clann. Irish clann (“offspring, children of the family”) and Scottish Gaelic clann, both from Old Irish cland, borrowed from owl plant, itself borrowed from Latin planta (“shoot, offspring”). a doublet of plant and planta.
Etymology from Wiktionary, CC BY-SA