spine (sp?n)n.1. The spinal column of a vertebrate.2. Zoology Any of various pointed projections, processes, or appendages of animals.3. Botany a. A strong, sharp-pointed outgrowth derived from a leaf or leaf part.b. Any of various similar sharp structures, such as a thorn.4. Something that resembles or suggests a backbone, as:a. The hinged back of a book.b. The crest of a ridge.5. Strength of character; courage or willpower.[Middle English, from Old French espine, from Latin sp?na.]American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.spine (spa?n) n1. (Anatomy) the spinal column2. (Botany) the sharply pointed tip or outgrowth of a leaf, stem, etc3. (Zoology) zoology a hard pointed process or structure, such as the ray of a fin, the quill of a porcupine, or the ridge on a bone4. (Printing, Lithography & Bookbinding) the back of a book, etc5. (Physical Geography) a ridge, esp of a hill6. strength of endurance, will, etc7. anything resembling the spinal column in function or importance; main support or feature[C14: from Old French espine spine, from Latin sp?na thorn, backbone] spined adjCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014spine (spa?n) n. 1. spinal column. 2. a hard, sharp-pointed outgrowth on a plant; thorn. 3. a stiff-pointed bone, process, or appendage, as the quill of a porcupine or the sharp rays in the fin of certain fishes. 4. resolution or courage; backbone. 5. a ridge, as of ground or rock. 6. the back of a book binding, usu. indicating the title and author. [1400?50; late Middle English