Convention

1. A meeting or an assembly of persons, esp. of delegates or representatives, to accomplish some specific object, -- civil, social, political, or ecclesiastical.
2. An agreement or contract less formal than, or preliminary to, a treaty; an informal compact, as between commanders of armies in respect to suspension of hostilities, or between states; also, a formal agreement between governments or sovereign powers; as, a postal convention between two governments.
3. An extraordinary assembly of the parkiament or estates of the realm, held without the king's writ, -- as the assembly which restored Charles II. to the throne, and that which declared the throne to be abdicated by James II.
4. The act of coming together; the state of being together; union; coalition.
5. General agreement or concurrence; arbitrary custom; usage; conventionality.