|1.||[ noun ] (informal) fortitude and determination|
|Synonyms:||guts gumption sand moxie grit|
"he didn't have the guts to try it"
|Related terms:||fortitude colloquialism|
|2.||[ noun ] a central cohesive source of support and stability|
|Synonyms:||anchor lynchpin linchpin keystone mainstay|
"faith is his anchor" "the keystone of campaign reform was the ban on soft money" "he is the linchpin of this firm"
|Related terms:||support anchor|
|3.||[ noun ] (anatomy,zoology) the series of vertebrae forming the axis of the skeleton and protecting the spinal cord|
|Synonyms:||spine vertebral_column back rachis spinal_column|
"the fall broke his back"
|Related terms:||skeletal_structure notochord chine axial_skeleton vertebra coccyx intervertebral_disc spinal_canal|
|4.||[ noun ] (computer science) the part of a network that connects other networks together|
"the backbone is the part of a communication network that carries the heaviest traffic"
|Related terms:||connection computer_network network|