quill vs primary quill

quill and primary quill both are nouns.

Word	Noun	Adjective	Verb	Adverb
quill	Yes	No	No	No
primary quill	Yes	No	No	No

As nouns, primary quill is a hyponym of quill; that is, primary quill is a word with a more specific, narrower meaning than quill:

quill: any of the larger wing or tail feathers of a bird
primary quill: one of the main flight feathers projecting along the outer edge of a bird's wing

Other hyponyms of quill include primary, primary feather, tail feather.

quill (noun)	primary quill (noun)
a stiff hollow protective spine on a porcupine or hedgehog	one of the main flight feathers projecting along the outer edge of a bird's wing
the hollow spine of a feather
any of the larger wing or tail feathers of a bird
pen made from a bird's feather