Nonround

Nonround is an English adjective used to describe something that is not round or not circular in shape. It is commonly employed as a descriptive term in fields such as geometry, design, and engineering to contrast with objects that possess a circular form or radial symmetry.

In geometry and design, nonround shapes encompass a wide range of forms, including ellipses, polygons, irregular blobs, and other figures lacking a perfect circle. A shape can be nonround yet still possess smooth curvature, like an ellipse, or be highly irregular with sharp corners and varying radii. The term emphasizes deviation from circularity rather than categorizing a specific alternative form.

In manufacturing and metrology, nonroundness (often described with the more common term out-of-round) refers to deviations of a part from an ideal circle. For cylindrical or spherical components, roundness is a key quality parameter; measurements assess radial deviations from a perfect circle as the part rotates. Instruments such as roundness testers, profilometers, and coordinate measuring machines are used to quantify nonroundness. Controlling roundness is important for fit, balance, and performance in precision assemblies.

Etymology-wise, nonround derives from the prefix non- meaning “not” and the adjective round, signaling negation of circularity. While the term is widely understood in technical contexts, more specific language (such as noncircular, nonroundness, or out-of-round) is often preferred depending on the domain. See also roundness, circularity, and geometric form.