zhī​zhù HSK7

mainstay

支柱 zhī​zhù
mainstay noun
a person or thing that acts as a primary source of strength, stability, or support

Manufacturing is the backbone of the country's economy.

pillar noun
a physical vertical structure used for support or reinforcement, such as a prop or shore

The miners are reinforcing the wooden pillars inside the mine.

Frequency

Movie subtitles
3.13 per million appears in 1% of films
Written text
13.1 per million

Details

HSK 2.0
Level 6
HSK 3.0
Level 7

Sources

Definitions
CC-CEDICT