Any fundamental support, structure, or infrastructure.
Courage, fortitude, or strength.
The series of vertebrae, separated by disks, that encloses and protects the spinal cord, and runs down the middle of the back in vertebrate animals.
A central cohesive source of stability and security; a person or thing that is critical to a system or organisation.
A pin inserted through holes at the end of an axle or shaft, so as to secure a wheel or shaft-mounted device.
To adopt as, or serve as, a central cohesive source of stability and security.