Acyclic

Part of speech: adjective

Pronunciation: /eɪˈsaɪklɪk/

Definitions

1. Not having any circular arrangement or repeating sequence, especially in organic chemistry where compounds are linear rather than ringed
2. Lacking any form of cyclical arrangement or repetition, this term often describes chemical compounds that are linear and graph structures that do not contain loops
3. Describes a structure or pattern that does not include any circular loops, commonly applied to molecules or graphs

Etymology: The prefix does most of the work here. The "a-" comes from Ancient Greek "ἀ-" (a-), a negating prefix equivalent to English "un-" or "non-", which English inherited through Proto-Hellenic and Proto-Indo-European roots. Attached to "cyclic", it simply reverses the sense: a thing that is not cyclic has no circles. The "cyclic" half traces back to Ancient Greek "κύκλος" (kúklos), meaning "circle" or "wheel", which passed into Latin as "cyclicus" and then into English as "cyclic" (with a French route through "cyclique"). The core idea is the circle, so "cyclic" describes anything that goes round in loops or returns to its starting point. "Acyclic" is an English formation built from these two parts, so it is a modern coinage made by joining an ancient prefix to an ancient root. Its use in chemistry and mathematics, where it describes molecules and graphs without closed loops, is a technical extension of the same plain sense of "without circles."

Synonyms: non-cyclic, linear

Antonyms: cyclic