connection vs backbone

connection and backbone both are nouns.

Word	Noun	Adjective	Verb	Adverb
connection	Yes	No	No	No
backbone	Yes	No	No	No

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

connection (noun)	backbone (noun)
the act of bringing two things into contact (especially for communication)	the part of a network that connects other networks together
shifting from one form of transportation to another	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
an instrumentality that connects	fortitude and determination
the process of bringing ideas or events together in memory or imagination	the series of vertebrae forming the axis of the skeleton and protecting the spinal cord
a supplier (especially of narcotics)	a central cohesive source of support and stability
(usually plural) a person who is influential and to whom you are connected in some way (as by family or friendship)
a relation between things or events (as in the case of one causing the other or sharing features with it)
a connecting shape
the state of being connected