What does cineol mean?
Cineol is a naturally occurring organic compound — a colorless, oily liquid terpene with the formula C10H18O — best known as the dominant component of eucalyptus oil. It carries a distinctive camphor-like aroma and produces the characteristic cooling sensation familiar from eucalyptus, cajuput, and many medicinal products. Because of these properties, cineol has long been valued as an expectorant in cough remedies and inhalants, and it also serves as a flavoring agent and a fragrance ingredient in soaps, detergents, and cosmetics. The quality of commercial eucalyptus oil is often graded by its cineol content, with pharmaceutical-grade oils expected to contain a high percentage of the compound. Although chemists and the essential-oil industry still use the term, the synonymous name 'eucalyptol' has become the preferred form in most contemporary scientific writing, so cineol today reads as slightly older or more trade-oriented vocabulary. Its story ties together botany, medicine, and perfumery in a single small, pungent molecule.
nounA colorless, oily liquid terpene (C10H18O) with a camphor-like odor and cooling taste, occurring chiefly in eucalyptus oil and used as a flavoring, fragrance ingredient, and expectorant. It is more commonly known by its alternative name, eucalyptol.
- A colorless liquid terpene alcohol (C10H18O), the principal constituent of eucalyptus oil, having a camphoraceous odor and used medicinally as an expectorant and in flavorings and perfumery.
"The chemist noted that cineol made up nearly eighty percent of the distilled eucalyptus oil."
"The essential oil was prized for its high cineol content."
"Inhaling steam laced with cineol helped ease her congestion."
As a mass noun denoting a chemical substance, cineol is usually uncountable; a plural appears mainly when referring to different varieties or measured samples of the compound.
"The lab analyzed several cineols derived from different eucalyptus species."
That bracing, camphor-cool rush you get from eucalyptus or a vapor rub? That's largely one single molecule — cineol.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of cineol
Cineol entered English in the nineteenth century, when chemists were systematically naming newly isolated plant-derived compounds. It is formed from elements relating to its source in aromatic oils combined with the '-ol' ending that denotes an alcohol in chemical nomenclature. The compound was identified as the principal constituent of eucalyptus oil, which led to its equally standard synonym, eucalyptol, a name now generally favored in scientific contexts. Related terms such as menthol and terpineol follow the same '-ol' naming pattern for fragrant natural alcohols.
How cineol is actually used
Cineol is chiefly a technical and commercial term, found in chemistry, pharmacology, and the essential-oil trade rather than everyday conversation. In modern usage, 'eucalyptol' is the far more common name for the compound, and scientific literature increasingly prefers it.
Easily confused with cineol
Cineole is not a different substance but simply the more common variant spelling of the same compound, cineol.