1. foundation or central aspect, bravery or strength
he has no backbone, it's the backbone of the industry/company
A 'backbone' is literally the spine of a person: "The scar ran from his neck to the end of his backbone." In a figurative sense, it refers to the main support system or foundations of a company, group, family or organisation: "My grandmother was always the backbone of the family." If we say a person has 'a lot of backbone', it means they have a lot of strength of character: "She will need a lot of backbone to stand up to the landlord." You can use this word in social and professional contexts. Similar meaning phrases include 'spine', 'the mainstay of', and 'the core of.'