›GOVERNMENT, LAWan agreement between two or more countries, formally approved by their governments: ratify/sign a treatyThe latest nation to ratify the treaty is France.an air/trade treatyThe US wants a new air treaty with the UK to lift barriers on the cities that each nations' carriers can serve.
›LAWa formal agreement between two people, companies, or organizations: Sales of partnership property should be conducted by private treaty or at auction. → See alsocontractnoun