Douglas Harper's Etymology Dictionary
Usage examples of "plumb-bob".
If you're interested in the sex of your unborn child, you can consult plumb-bob danglers all you want (left-right, a boy.
Every scrap of land in the town was owned by the Church, and the Holy Surveyors of Rome had (or so Jack phant’sied) come out here and planted Trinitarian transits on the land that had been miraculously reclaimed from Lake Texcoco and hung holy plumb-bobs made of saints’ skulls and stretched cords of spun angels’ hair, driven crucifixes into the ground at strategickal Vertices, and platted the land into quadrilaterals, each one butted snugly against the next.