Board. [bord]. Noun. [From Middle English bord, a piece of sawed lumber or a border]. 1. A piece of sawed wood that is longer than it is thick. 2. A group of people who have managerial or advisory power. 3. A flat, rectangular surface. 4. Food provided in exchange for pay. Use the drop-down menus to answer each question about the dictionary definition. What is the most commonly used definition of board? What is the source language of board?