1. A prominent supporter
   - pillar 
2. A central cohesive source of support and stability
   - anchor, keystone, backbone, linchpin, lynchpin 
3. The forestay that braces the mainmast

Derived forms: mainstays

Type of: admirer, booster, champion, forestay, friend, protagonist, support, supporter

Encyclopedia: Mainstay

• North Equatorial Current
• North Frigid Zone
• North Germanic
• North Germanic language
• North Island
• north island edelweiss
• North Korea
• North Korean
• North Korean monetary unit
• North Korean won
• north northeast
• north northwest
• North Pacific
• North Peak
• North Platte
• North Platte River
• North Pole
• North Sea
• north side
• North Star
• North Star State
• North Temperate Zone
• North Vietnam
• North Vietnamese
• north wind