countable/uncountable an arrangement between two or more people, groups, or countries by which they agree to work together to achieve somethingalliance between: an alliance between conservative Democrats and moderate Republicans
alliance with: Successive French governments maintained the alliance with Russia.
enter into/form/forge an alliance: Independent companies are encouraged to form strategic alliances to help them compete.
in alliance with someone (=working together with someone): a marketing campaign by Apple in alliance with other names