backbone >> /ˈbækˌboʊn/
Definition: [noun] The series of vertebrae extending from the skull to the pelvis; the spine.
Example: prickles of sweat broke out along her backbone
Definition: [noun] The chief support of a system or organization; the mainstay.
Example: these firms are the backbone of our industrial sector
Definition: [noun] A high-speed, high-capacity digital connection which forms the axis of a local or wide area network.
Example: The first major project completed was the digital backbone network, which spans the entire country since its completion in February this year.