essential oil

noun

: any of a class of volatile oils that give plants their characteristic odors and are used especially in perfumes and flavorings, and for aromatherapy compare fixed oil

Examples of essential oil in a Sentence

Recent Examples on the Web

It’s made with a mix of essential oils to fuel hair growth, including rosemary and castor oils. — Reece Andavolgyi, InStyle, 26 Aug. 2026

To deal with odors that might seep in from other rooms, buy a few air fresheners or even an essential oil diffuser to help conceal anything offensive. — Bestreviews, Mercury News, 21 Aug. 2026

How to Use Essential Oils to Repel Flies Always dilute essential oils before using them for pest control. — Louise Parks, Martha Stewart, 21 Aug. 2026

The basic components of most sprays are magnesium chloride and distilled water, with some brands adding aloe vera or essential oils. — Samantha Agate, Sacbee.com, 21 Aug. 2026

Word History

First Known Use

1674, in the meaning defined above

Rhymes for essential oil

• aerofoil
• cinquefoil
• hydrofoil
• quatrefoil
• airfoil
• benzoyl
• despoil
• embroil
• etoile
• gargoyle
• recoil
• subsoil

Medical Definition

essential oil

noun

: any of a large class of volatile odoriferous oils of vegetable origin that give plants their characteristic odors and often other properties, that are obtained from various parts of the plants (as flowers, leaves, or bark) by steam distillation, expression, or extraction, that are usually mixtures of compounds (as aldehydes or esters), and that are used often in the form of essences in perfumes, flavorings, and pharmaceutical preparations

called also ethereal oil, volatile oil

compare fatty oil, fixed oil