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
the property of being an amount by which something is less than expected or required; "new blood vessels bud out from the already dilated vascular bed to make up the nutritional deficit"
an excess of liabilities over assets (usually over a certain period); "last year there was a serious budgetary deficit"
(sports) the score by which a team or individual is losing
a deficiency or failure in neurological or mental functioning; "the people concerned have a deficit in verbal memory"; "they have serious linguistic deficits"