Nonslanting

Nonslanting is an adjective used to describe objects, surfaces, or references that have no tilt relative to a reference plane or direction. In common usage, "nonslanting" roughly corresponds to being level or horizontal for surfaces meant to be parallel to the earth's surface, or vertical (plumb) for upright structures, depending on the reference. The term is not widely used in formal standards, where more specific terms like horizontal, level, or plumb are preferred.

In surveying, civil engineering, and construction, nonslanting conditions are those with zero slope along the reference plane. A nonslanting floor is horizontal (zero slope). A nonslanting wall is vertical (plumb). Determining and maintaining nonslanting states relies on leveling instruments such as spirit levels and laser levels, as well as careful calibration of reference points and datum planes.

In mathematics and computer science, a surface or function is described as nonslanting with respect to a chosen direction if its slope in that direction is zero; equivalently, the directional derivative along that axis is zero. A plane of constant height is a simple example of a nonslanting surface with respect to vertical direction.

Applications include architectural design, furniture making, and quality control, where keeping components nonslanting ensures proper fit, function, and aesthetics. Tolerance standards specify permissible deviations from the reference plane or direction, which govern acceptable levels of slanting in a project.

See also: horizontal, level, plumb, slope, incline, gradient, datum.