A plumb bob is a simple yet effective tool used in construction and carpentry. It consists of a weight, often shaped like a pointed metal object, attached to a string or line. When suspended, the weight hangs vertically due to gravity, providing a reliable reference for determining true vertical alignment. The symbol "🪝🔷" represents the combination of a hook (🪝) and a blue diamond (🔷), visually alluding to the shape and color of a plumb bob.