expression, godan verb (-ru)
be related by blood; be blood-related
Often used in the form 血が繋がっている to describe a blood relationship. Emphasizes biological connection rather than legal or social ties.
彼とは血が繋がっていないが、本当の兄弟のように思っている。
We aren't related by blood, but I think of him as a real brother.
Just because you're blood-related doesn't necessarily mean you'll get along as a family.