Ascaridia galli vs roundworm

Ascaridia galli and roundworm both are nouns.

Word	Noun	Adjective	Verb	Adverb
Ascaridia galli	Yes	No	No	No
roundworm	Yes	No	No	No

As nouns, roundworm is a hypernym of Ascaridia galli; that is, roundworm is a word with a broader meaning than Ascaridia galli:

Ascaridia galli: intestinal parasite of domestic fowl
roundworm: unsegmented worms with elongated rounded body pointed at both ends; mostly free-living but some are parasitic

Other hypernyms of Ascaridia galli include nematode, nematode worm.

Ascaridia galli (noun)	roundworm (noun)
intestinal parasite of domestic fowl	unsegmented worms with elongated rounded body pointed at both ends; mostly free-living but some are parasitic
	infections of the skin or nails caused by fungi and appearing as itching circular patches