backbone vs spinal canal

backbone and spinal canal both are nouns.

Word	Noun	Adjective	Verb	Adverb
backbone	Yes	No	No	No
spinal canal	Yes	No	No	No

backbone (noun)	spinal canal (noun)
the part of a network that connects other networks together	the canal in successive vertebrae through which the spinal cord passes
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
fortitude and determination
the series of vertebrae forming the axis of the skeleton and protecting the spinal cord
a central cohesive source of support and stability