Yönselliin

Yönselliin is a term used in theoretical discussions to denote directional dependence of a property within a system. When a property exhibits yönselliin, its measured value can change with the direction or orientation of measurement.

There is no universally agreed definition, so the term is often used as an informal label for anisotropy or orientation-dependent phenomena across fields such as physics, materials science, optics, and biology.

Examples include crystals whose elastic, magnetic, or electronic properties vary with crystallographic direction; optical materials with direction-dependent refractive indices; and sensory or neural systems whose responses are tuned to stimulus direction.

The etymology of yönselliin is not established in standard literature; it may draw on Turkic roots for direction, but its use remains informal. When used, it should be defined explicitly with the property, direction, and context.

See also anisotropy, directional dependence, orientation, directionality.