Urochordata vs phylum

Urochordata and phylum both are nouns.

Word	Noun	Adjective	Verb	Adverb
Urochordata	Yes	No	No	No
phylum	Yes	No	No	No

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

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

Urochordata (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