allianceal·li·ance /əˈlaɪəns/ noun [countableC]COMMERCE1an agreement between two or more organizations to work togetherThe two insurance companies agreed to form an alliance.
alliance betweenan alliance between the two media groups
alliance withThe firm said it may need to form an alliance with another company to survive.
→ strategic alliance2in alliance with if two or more organizations are in alliance with each other, they work togetherThe Japanese car company said it would only enter Eastern Europe in alliance with a European manufacturer.