subkingdom vs taxon

subkingdom and taxon both are nouns.

Word	Noun	Adjective	Verb	Adverb
subkingdom	Yes	No	No	No
taxon	Yes	No	No	No

As nouns, taxon is a hypernym of subkingdom; that is, taxon is a word with a broader meaning than subkingdom:

subkingdom: (biology) a taxonomic group comprising a major division of a kingdom
taxon: animal or plant group having natural relations

Other hypernyms of subkingdom include taxonomic category, taxonomic group.

subkingdom (noun)	taxon (noun)
(biology) a taxonomic group comprising a major division of a kingdom	animal or plant group having natural relations