multilateral
adjective
uk/ˌmʌltiˈlætərəl/ usinvolving or affecting several different countries, organizations, etc.:
Attempts to reach a comprehensive multilateral agreement with binding rules have thus far not been successful.
The next round of multilateral negotiations will commence next month.
Australia remains strongly committed to the multilateral trading system.
Compare
bilateral
unilateral
multilaterally
adverb uk/ˌmʌltiˈlætərəli/
Trading policies of individual WTO members are examined multilaterally by turn, and in depth.