A statement issued, usually by a corporation, ostensibly explaining their mission--the ultimate goal and end of each action of each employee.
The problem with mission statements is that every corporation in the world (excepting incorporated charities and the like) has the same mission. I've often said that if I find a company with the mission statement "Our mission is to make a big pile of dough" that I would buy three of whatever they sell out of sheer admiration for their honesty.