ice circle

Etymology
. From being a circular disc made of ice.

Noun

 * 1) A phenomenon that occurs on rivers during winter, where floating ice caught in an eddying flow will rotate around, knocking off its distant edges, forming a floating revolving circular disk, slowing turning under the influence of the underlying vortex current; when the temperature conditions are not too warm, leading to ice breakup and fragility, and not too cool, freezing over the entire surface.

Translations

 * Esperanto:
 * French: disque de glace
 * Indonesian: cakram es
 * Swedish: ,