In a circular manner or direction; in a way that forms a circle or moves around and returns to the starting point.
From 'circular' plus '-ly,' the adverb-forming suffix from Old English '-lice.' The '-ly' suffix transforms adjectives into adverbs by adding the idea of 'in the manner of.'
The '-ly' suffix is so automatic that English speakers barely notice it, but without it we couldn't easily make adverbs from adjectives—and languages without this feature have much more complicated adverb systems.
Complete word intelligence in one call. Free tier — 50 lookups/day.