Why are Rayonnant rose windows associated with radial patterns?

Rayonnant rose windows are associated with radial patterns because the term "Rayonnant" itself is derived from the radiating character of the rose window tracery.12

During the 13th century, architects of the Rayonnant style shifted their focus from achieving great structural size to creating rich visual effects through elaborate decoration. The tracery within these large circular windows typically featured a series of radiating forms, often tipped by pointed arches, which created a distinct sunburst or radial effect. Because these radial patterns became a defining and most characteristic feature of the style's aesthetic, the term "Rayonnant"—meaning "radiating"—was adopted to describe this phase of Gothic architecture.123