backbones
nounUK /ˈbæk.bəʊnz/
US /ˈbæk.boʊnz/
The backbones are the line of small bones that run down the middle of your back.
The doctor felt along the child's backbones to check her spine.
OTHER MEANINGS
2. The most important support or strength of a group or system.
Small farmers are the backbones of the local economy.
3. A strong, firm quality of character.
Her honesty and courage showed real backbone.
4. The main connecting line of a computer or communication network.
The internet backbone carries data between cities.