main entry word vs descriptor

main entry word and descriptor both are nouns.

Word	Noun	Adjective	Verb	Adverb
main entry word	Yes	No	No	No
descriptor	Yes	No	No	No

As nouns, descriptor is a hypernym of main entry word; that is, descriptor is a word with a broader meaning than main entry word:

main entry word: the form of a word that heads a lexical entry and is alphabetized in a dictionary
descriptor: the phonological or orthographic sound or appearance of a word that can be used to describe or identify something

Other hypernyms of main entry word include form, signifier, word form.

main entry word (noun)	descriptor (noun)
the form of a word that heads a lexical entry and is alphabetized in a dictionary	a piece of stored information that is used to identify an item in an information storage and retrieval system
	the phonological or orthographic sound or appearance of a word that can be used to describe or identify something