annular adj.

"ring-shaped," 1570s, from French annulaire (16c.) or directly from Medieval Latin annularis "pertaining to a ring," from annulus, misspelled diminutive of Latin anus "ring" (see anus).

An annular eclipse (1727) is one in which the dark body of the moon is smaller than the disk of the sun, so that at the height of it the sun, due to the moon's remoteness from Earth, appears as a ring of light. Related: Annularity.