Cyclic is from Late Latin cyclicus, from Greek kyklikos ('moving in a circle'), from kyklos ('circle, wheel'). The ancestry passes through Ancient Greek kyklikos and Ancient Greek kyklos. In present use as an adjective, it means "recurring in cycles; pertaining to a cycle", keeping the historical formation close to the word's ordinary semantic work. Related words include cycle, cyclical, and cyclone; derived forms include cyclically and cyclicity. Its contrast set includes linear, acyclic, and aperiodic, which clarifies the semantic boundary of the modern word.