- (countable) The backbone is the bones in a person's or animal's back.
- (countable) or (uncountable) If you have backbone, you do not back down easily. You stand up for yourself.
- If you had any backbone you wouldn't let people tell you what to do all the time.
- (countable) The backbone of something is what holds it together or makes it strong.
- Customer service is the backbone of our business.