backbone

Reading level: hard

Estimated CEFR level: C2 — Proficiency

Estimated from word frequency; not an official CEFR classification.

Definition

noun a central cohesive source of support and stability
noun fortitude and determination
noun the series of vertebrae forming the axis of the skeleton and protecting the spinal cord

From Middle English bakbon, bakebon, bac-bon; equivalent to back + bone. Compare the semantically analogous English ridgebone.

They ain’t got any backbone. — The Adventures of Tom Sawyer, Complete, Mark Twain
'Four,--four backbones,' said Haymoss, decisively. — Two on a Tower, Thomas Hardy
No, Marjorie hadn't enough backbone. — Rilla of Ingleside, L. M. (Lucy Maud) Montgomery

anchor, mainstay, keystone, linchpin, lynchpin

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