subphylum Urochorda vs phylum

subphylum Urochorda and phylum both are nouns.

Word	Noun	Adjective	Verb	Adverb
subphylum Urochorda	Yes	No	No	No
phylum	Yes	No	No	No

As nouns, phylum is a hypernym of subphylum Urochorda; that is, phylum is a word with a broader meaning than subphylum Urochorda:

subphylum Urochorda: tunicates
phylum: (biology) the major taxonomic group of animals and plants; contains classes

subphylum Urochorda (noun)	phylum (noun)
tunicates	(biology) the major taxonomic group of animals and plants; contains classes
	(linguistics) a large group of languages that are historically related