Made to be or treated as a cousin; related or connected as if by kinship.
From 'be-' plus 'cousined' (related by 'cousin'); a rare construction showing how 'be-' could be applied to kinship terms to indicate relationship status.
This wonderfully archaic word appears in Shakespeare and period texts to indicate a kind of adopted or honorary kinship—'they were becousined by marriage'—showing how Renaissance English played with family terminology.
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