English 'cousin' descends from Old French 'cosin,' from Latin 'consobrinus' meaning 'mother's sister's child' — a compound built on 'soror' (sister), itself from PIE *swésor, making the word etymologically the child of 'sisters,' even though it now covers all first-cousin relationships.
A child of one's uncle or aunt; more broadly, any relative descended from a common ancestor beyond the immediate family.
From Old French 'cosin,' from Latin 'consobrinus' meaning 'mother's sister's child' — a compound of 'con-' (together, with) and 'sobrinus,' itself derived from 'soror' meaning 'sister,' from PIE *swésor. In Classical Latin, 'consobrinus' was the specific term for a first cousin on the maternal side; other types of cousins had different terms. Old French collapsed these distinctions into a single word, which English borrowed, further generalising the meaning over time. Key roots: *swésor (Proto-Indo-European: "sister"), soror (Latin: "sister (from *swésor via regular sound changes