/əˈsiːd tə ə ˈtriːti/ – Phrase
Definition: tham gia hiệp ước quốc tế.
A more thorough explanation: To formally join a treaty already in force between other parties. This typically involves agreeing to be bound by the terms and conditions of the treaty.
Example: The United States acceded to the Paris Agreement on Climate Change in 2016, committing itself to reducing greenhouse gas emissions.