spine vs glochidium

spine and glochidium both are nouns.

Word	Noun	Adjective	Verb	Adverb
spine	Yes	No	No	No
glochidium	Yes	No	No	No

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

Other hyponyms of spine include glochid.

spine (noun)	glochidium (noun)
a sharp rigid animal process or appendage; as a porcupine quill or a ridge on a bone or a ray of a fish fin	a barbed spine or bristle (often tufted on cacti)
the part of a book's cover that encloses the inner side of the book's pages and that faces outward when the book is shelved
the series of vertebrae forming the axis of the skeleton and protecting the spinal cord
a small sharp-pointed tip resembling a spike on a stem or leaf
any sharply pointed projection