essential oils plural noun

Oils which give plants their fragrance, used in cosmetics, toiletries, etc and in aromatherapy (also called ethereal oils or volatile oils)

essential organs plural noun (botany)

Stamens and carpels

in essence

Basically, fundamentally

of the essence

Of the utmost importance

volatile /volˈə-tīl or (N American) -til or -təl/

1. Evaporating very quickly
2. Explosive
3. Subject to sudden changes in emotional state
4. Flighty, apt to change
5. (of stock markets, etc) showing rapid changes in prices
6. Transient, short-lived, fleeting
7. Denoting a type of memory (volatile memory) that does not retain information after the power supply is turned off, opp to non-volatile (computing)
8. Capable of flying
9. Moving lightly and rapidly about

1. A volatile substance
2. A creature capable of flying (obsolete)

volˈatileness or volatility /-tilˈ/ noun

volˈatilīzable or volˈatilīsable (or /-atˈ/) adjective

volatilīzāˈtion or volatilīsāˈtion noun

volˈatilize or volˈatilise (or /-atˈ/) transitive verb and intransitive verb

To make or become volatile

1. To cause to evaporate
2. To make light, unsubstantial or delicate (figurative)

volatile alkali noun (obsolete)

Ammonia

volatile oils see essential oils under essence