Backbone
From BiblePortal Wikipedia
Webster's Dictionary [1]
(1): (n.) The column of bones in the back which sustains and gives firmness to the frame; the spine; the vertebral or spinal column.
(2): (n.) Anything like , or serving the purpose of, a backbone.
(3): (n.) Firmness; moral principle; steadfastness.
King James Dictionary [2]
Backbo'Ne, n. back and bone. The bone of the back or the spine.