emotional backbone; support; core strength
Metaphorical use referring to a person's inner strength, resolve, or the central supporting element of an organization or plan.
He is the backbone of the team.
That policy needs a solid backbone.
network backbone
Technical computing term for the high-capacity core infrastructure of a network.
The internet backbone is made up of optical fiber.
His conviction has become the backbone of the team.
This company built the backbone of a nationwide network.
She has a strong inner backbone, so she isn't shaken by criticism.