gradational

Gradational is an adjective describing a process or state characterized by gradual change or a transition that lacks a sharp boundary. It derives from gradation, the act or process of forming gradual steps, and shares close relation to gradient and gradualism. In use, gradational emphasizes continuity and incremental variation over a space, time, or spectrum.

Common contexts include geology and geomorphology, where a gradational contact between rock units shows a gradual change in mineralogy, texture, or composition across a distance, rather than an abrupt boundary. This can reflect slow sedimentation, diagenesis, or weathering processes that blend units.

In design, art, and imaging, gradational refers to gradual transitions between colors or tones, often implemented as gradients. Gradational shading or color ramps are used to achieve depth, volume, or smooth backgrounds.

Other uses include ecology or climate science to describe zones that transition gradually from one ecosystem or climate regime to another. In general discourse, gradational describes any phenomenon that changes progressively, without a discrete cutoff.

See also: gradient, gradation, gradual.