Plumb line
A weighted string held against a surface — a simple test for whether a wall stands true.
A plumb line in a dream is the dream's image of a simple, undeniable test for whether a built thing stands true. The weight does not negotiate; the string falls straight down, and the wall is either aligned with that line or it is not. The dream brings the plumb line when something in your life — a relationship, a piece of work, a stated principle — is being measured against a reference it cannot argue with. A plumb line returning the wall as true is the dream affirming the honest build. A plumb line showing the wall leaning, with the gap visible against the string, is the dream noting that the construction has gone off true and no amount of plastering will fix the underlying lean.