a friend who is like a sister, and may be a member of your framily!
they became fristers when they siblings started dating. they were part of the framily
they were like fristers after a short time as they got on as well as sisters
When members of your sibling's boyfriend/girlfriend's family become close friends. They are not your siblings inlaws yet and may never be. You will always consider them FRAMILY.
My new Framily are like sisters but not related to me at all.