What does cineole mean?
Cineole, also known by its common name eucalyptol, is a naturally occurring organic compound — specifically a cyclic monoterpene ether with the formula C₁₀H₁₈O — that makes up the bulk of eucalyptus oil and appears in smaller quantities in laurel, tea tree, rosemary, and other aromatic plants. A colorless liquid with a cool, camphor-like smell reminiscent of the eucalyptus tree itself, cineole is prized industrially as a flavoring and fragrance ingredient and is used in medicine as an expectorant, helping to loosen mucus and relieve coughs and congestion. Its concentration is a key measure of quality in commercial eucalyptus oils, and oils described as 'cineole-rich' are especially sought after for therapeutic use. The name derives from the Greek verb kinein, meaning 'to move', a reference to the compound's optical activity — its ability to rotate the plane of polarized light. Though largely confined to scientific and trade contexts, cineole is a useful term for anyone interested in the chemistry behind familiar herbal remedies and scents.
nounA colorless, oily liquid monoterpene ether (chemical formula C₁₀H₁₈O), also known as eucalyptol, that is the principal component of eucalyptus oil and occurs in many other essential oils; used medicinally as an expectorant and in flavorings and fragrances.
- A colorless liquid terpene ether, C₁₀H₁₈O, the chief constituent of eucalyptus oil, having a camphoraceous odor and used in medicine as an expectorant and in flavorings and perfumery.
"The sharp, camphor-like aroma radiating from the crushed leaves comes chiefly from cineole."
"Eucalyptus oil is prized for its high cineole content, which gives it both its medicinal punch and its penetrating aroma."
"Pharmacists once relied on cineole's expectorant properties to ease chest congestion."
Rarely pluralized; when referring to different compounds of this type, the plural 'cineoles' may appear in technical literature.
"Several cineoles have been isolated from the plant's essential oil."
Cineole owes its name to a quirk of chemistry: it was christened for the way it rotates polarized light — from the Greek word for 'to move'.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of cineole
Cineole entered English in the late nineteenth century, coined by chemists studying the constituents of eucalyptus oil. The word combines Greek kinein ('to move'), via elements relating to motion, with the '-ole' ending derived from Latin oleum ('oil'), a suffix commonly attached to names of volatile oil constituents. The Greek root kinein also underlies such words as kinetic, cinematic, and kinesiology. The compound is equally well known under its alternative name eucalyptol.
Related word forms
How cineole is actually used
Cineole is a technical term used mainly in chemistry, pharmacology, aromatherapy, and the essential-oils industry; it is rarely encountered in everyday speech. The synonym 'eucalyptol' is at least as common in scientific literature, and '1,8-cineole' is the precise systematic name. Both spellings 'cineole' and 'cineol' are accepted.
Easily confused with cineole
Nicotine is a stimulant alkaloid found in tobacco, whereas cineole is a terpene ether that gives eucalyptus oil its characteristic scent.