spines

noun

The narrow, bound edges of books, often displaying the title and author.

"She arranged the books by their spines."

noun

Sharp, pointed projections on plants or animals, primarily for protection or support.

"The hedgehog's spines protected it."

Thesaurus

Synonyms: reel, spin around, gyrate, whirl, twisting, twirl, twist, spin out, birl, tailspin