1. involving or participated in by more than two parties, groups, or countries
Usage: often used in political and diplomatic contexts
2. having many sides
Usage: geometric or technical usage

Examples

• The multilateral trade agreement involved six different countries.
• NATO is a multilateral defense alliance.
• The peace talks required multilateral cooperation from all parties.
• They signed a multilateral treaty to protect the environment.
• The multilateral approach proved more effective than bilateral negotiations.
• A multilateral figure has more than four sides.
• The organization promotes multilateral dialogue on global issues.