book vs backbone

book and backbone both are nouns.

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

book (noun)	backbone (noun)
physical objects consisting of a number of pages bound together	the part of a network that connects other networks together
a number of sheets (ticket or stamps etc.) bound together on one edge	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
a written work or composition that has been published (printed on pages bound together)	fortitude and determination
a written version of a play or other dramatic composition; used in preparing for a performance	the series of vertebrae forming the axis of the skeleton and protecting the spinal cord
a compilation of the known facts regarding something or someone	a central cohesive source of support and stability
a major division of a long written composition
a collection of rules or prescribed standards on the basis of which decisions are made
a collection of playing cards satisfying the rules of a card game
a record in which commercial accounts are recorded

book (verb)	backbone (verb)
engage for a performance
record a charge in a police register
arrange for and reserve (something for someone else) in advance
register in a hotel booker