backbone
Cross references: 1. fortitude back.bone \-'bo-n, -.bo-n\ n 1: SPINAL COLUMN, SPINE 2a: a chief mountain ridge, range, or system 2b: the foundation or most substantial or sturdiest part of something 3: firm and resolute character 4: the back of a book usu. lettered with the title and the author's and pub lisher's names