back ‧ bone /ˈbækbəʊn $ -boʊn/ BrE AmE noun
1 . [countable] the row of connected bones that go down the middle of your back SYN spine
2 . the backbone of something the most important part of an organization or group of people:
Farmers are the backbone of this community.
3 . [uncountable] courage and determination:
Stuart doesn’t have the backbone to be a good manager.