Backbone

Part of speech: noun

Pronunciation: /ˈbækˌbəʊn/

Definitions

1. The central structural support of a body, consisting of vertebrae stacked together, that protects the spinal cord and provides framework for the skeleton
2. The primary support structure of an organism, composed of vertebrae that encase the spinal cord while also enabling flexibility and mobility
3. A crucial anatomical component made up of interlocking vertebrae that safeguards the central nervous system and supports overall body structure

Etymology: "Backbone" is about as transparent as compounds get: it joins "back" and "bone," the two words doing exactly what they say. The Middle English forms "bakbon" and "bakebon" show the compound taking shape in the medieval period, when the spine was simply the bone along the back. The more telling comparison is "ridgebone," an older English word for the same structure. It describes the spine as the ridge running down the animal's body, a picture of the backbone as a mountain range along the body. "Backbone" won out because it names the body's rear side directly, while "ridgebone" points to the shape the spine makes under the skin. Over time, the word's sense stretched from the bony column itself to the figurative idea of firmness and resolve, as in someone "having backbone." That extension is the same logic as the physical meaning: the spine holds the body upright, so the word came to mean what keeps a person steady.

Synonyms: spine, vertebrae, support, strength, foundation

Antonyms: weakness, fragility, insecurity, instability, vulnerability