(mathematics) calculation of the value of a function between the values already known
a message (spoken or written) that is introduced or inserted; "with the help of his friend's interpolations his story was eventually told"; "with many insertions in the margins"
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