circular

The word 'circular' traces its lineage to the Latin circularis, meaning 'of a circle'. This adjective was formed from circulus, a diminutive of circus, which denoted a 'ring' or 'circle'. The Latin circus itself is derived from the Greek kirkos, likely meaning 'ring', which shares a Proto-Indo-European root with Old English hring, also meaning 'ring'. The semantic journey is direct: from the physical concept of a round shape, the meaning extended to describe motion along that shape and, metaphorically, to arguments that loop back on themselves. The noun sense, referring to a document distributed to a circle of people, emerged in the 18th century.

Structure: circul (circle) + ar (adjective suffix) circul (from Latin circulus, meaning 'small ring, circle'); ar (from Latin adjectival suffix -aris, meaning 'of or pertaining to').