Straightness/ˈstreɪtnəs/ Definition 1 of 2Pro Tip 1/3Physical Objects Refers to the shape of physical objects; implies no curves or angles. Check the straightness of the ruler before purchasing. Pro Tip 2/3Clear Path Describes a path that is direct and without detours. His arrow flew with straightness toward the target. Pro Tip 3/3Proper Alignment Often used to describe the correct positioning or alignment of parts. Ensure the straightness of the shelves on the wall.