athar vs volatile oil

athar and volatile oil both are nouns.

Word	Noun	Adjective	Verb	Adverb
athar	Yes	No	No	No
volatile oil	Yes	No	No	No

As nouns, volatile oil is a hypernym of athar; that is, volatile oil is a word with a broader meaning than athar:

athar: essential oil or perfume obtained from flowers
volatile oil: an oil having the odor or flavor of the plant from which it comes; used in perfume and flavorings

Other hypernyms of athar include essential oil.

athar (noun)	volatile oil (noun)
essential oil or perfume obtained from flowers	an oil having the odor or flavor of the plant from which it comes; used in perfume and flavorings