| a distilled oil, esp. one obtained from plant tissue, as distinguished from glyceride oils by their volatility and failure to saponify. |

| volatile oil n. A rapidly evaporating oil, especially an essential oil, that does not leave a stain. |
volatile oil n.
A rapidly evaporating oil of plant derivation, especially an essential oil, that is capable of distillation and that does not leave a stain. Also called ethereal oil.