Related Clues:

• Joined by a treaty
• United by treaty
• Affiliated
• In a league, say
• Word in many union names
• In a partnership
• Like Cuba and Venezuela, e.g.
• Worked together (with "up")
• Federated
• Working (with)
• Formed a partnership
• Owl's cry
• On the same page
• Joined together for a purpose
• Joined to, combined with