The respective rights and claims of matrikin and patrikin are well exemplified in the arrangement of marriages.
— Meyer Fortes, Kinship and the Social Order, 1970
These words refer respectively to one's maternal and paternal relatives. The matr- and patr- parts are Latin, but the kin part is from English's earliest Germanic days. Kin originally referred to a group of people of common ancestry, but your kin are also the people who likely come to mind when you think of your relatives. This meaning is the word's most common one, and it's a meaning the word has had since the 9th century.
Other family words related to kin are kinfolk (and kinsfolk), kindred, kinship, and kinsman and kinswoman.