aniseed oil vs essential oil

aniseed oil and essential oil both are nouns.

Word	Noun	Adjective	Verb	Adverb
aniseed oil	Yes	No	No	No
essential oil	Yes	No	No	No

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

aniseed oil: an essential oil extracted from the seeds of Pimpinella anisum (aniseed), having a pungent liquorice-like smell.
essential oil: an oil having the odor or flavor of the plant from which it comes; used in perfume and flavorings

Other hypernyms of aniseed oil include volatile oil.

aniseed oil (noun)	essential oil (noun)
an essential oil extracted from the seeds of Pimpinella anisum (aniseed), having a pungent liquorice-like smell.	an oil having the odor or flavor of the plant from which it comes; used in perfume and flavorings