>Nexus [nek suhs] (noun)

MSWORD’s definition:
1. A connection or link associating two or more people or things
2. a group or series of connected people or things
3. the center or focus of something
4. a specialized part of the cellular membrane that helps cells to communicate or adhere

Usage:
Sally was the nexus that held the kept the ladies social group together.
The nexus of their Center for Children was simply that everyone deserved love.