a sharp rigid animal process or appendage; as a porcupine quill or a ridge on a bone or a ray of a fish fin
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 title and author were printed on the spine of the book"
a small sharp-pointed tip resembling a spike on a stem or leaf
a short strip of material attached to or projecting from something in order to facilitate opening or identifying or handling it; "pull the tab to open the can"; "files with a red tab will be stored separately"; "the collar has a tab with a button hole"; "the filing cards were organized by cards having indexed tabs"