A sharp appendage to any of a plant; a thorn.
- The spinal column of a vertebrate.
- Zoology Any of various pointed projections, processes, or appendages of animals.
- Botany A strong, sharp-pointed, usually woody outgrowth from a stem or leaf; a thorn.
- Something that resembles or suggests a backbone, as:
- The hinged back of a book.
- The crest of a ridge.
- Strength of character; courage or willpower.