backbone

/ˈbækˌboʊn/

a central cohesive source of support and stability

中文释义：支柱；骨干；脊柱

Small businesses are the backbone of the local economy, providing jobs and services.

小企业是当地经济的支柱，提供就业和服务。

The spine, or backbone, protects the spinal cord and supports the body.

脊柱保护脊髓并支撑身体。