主要成分;支柱;中枢
the most important part of something, providing support for everything else
Farming is the backbone of the country's economy. 农业是这个国家的经济支柱。
Church members are the backbone of society in this town.
Tourism is the backbone of our economy.
These registered nurses are the backbone of both private and public medical establishments.
Evidence from surveillance cameras forms the backbone of the prosecution's case.
See also: backbone (STRENGTH)