eau de cologne vs essence

eau de cologne and essence both are nouns.

Word	Noun	Adjective	Verb	Adverb
eau de cologne	Yes	No	No	No
essence	Yes	No	No	No

As nouns, essence is a hypernym of eau de cologne; that is, essence is a word with a broader meaning than eau de cologne:

Other hypernyms of eau de cologne include perfume.

eau de cologne (noun)	essence (noun)
a perfumed liquid made of essential oils and alcohol	a toiletry that emits and diffuses a fragrant odor
	the choicest or most essential or most vital part of some idea or experience
	the central meaning or theme of a speech or literary work
	any substance possessing to a high degree the predominant properties of a plant or drug or other natural product from which it is extracted