Which tool is used for leveling, plumbing, and serving as a straight edge?

The tool used for leveling, plumbing, and serving as a straight edge is the level. This instrument is essential in masonry and construction because it ensures that surfaces are perfectly horizontal or vertical. A level typically contains a bubble vial that indicates whether the surface being measured is level; when the bubble is centered between the lines, it confirms that the surface is straight and even.

Levels come in various forms, including spirit levels, laser levels, and digital levels, each suited for different tasks but all serving the fundamental purpose of ensuring precision in building and installation. By accurately determining the levelness of materials and structures, the level helps to prevent structural issues and ensures that the work adheres to design specifications.

While other instruments like plumb bobs are useful for vertical alignment, and measuring sticks can measure lengths, they do not provide the same direct functionality for checking both horizontal and vertical alignments in a straightforward manner as a level does.