sorority (n.)

• affiliation
• alignment
• alliance
• amalgamation
• association
• brotherhood
• club
• coalescence
• coalition
• combination
• companionship
• comradeship
• confederacy
• confederation
• consolidation
• copartnership
• federation
• fellowship
• fraternity
• fraternization
• freemasonry
• fusion
• guild
• hookup
• inclusion
• incorporation
• integration
• league
• merger
• order
• partnership
• sisterhood
• society
• sodality
• tie-in
• tie-up
• unification
• union