Before it described the people who teach at universities, 'faculty' described the powers those people supposedly possessed. The Latin source, facultas, meant raw capability — the ability to get things done — and derived from facilis ('easy'), itself from facere ('to do'). Old French compressed this into faculté, and Middle English borrowed it around the 1380s. Early usage was philosophical: writers spoke of the 'faculty of reason' or the 'faculty of sight,' treating human abilities as discrete mental organs. Universities, meanwhile, had been using the Latin form to label their divisions of study since the twelfth century. When the English word arrived, it absorbed both meanings. By the sixteenth century, 'faculty' could refer to the teaching body itself, not just the department. American English cemented this shift — in the United States, 'faculty' almost always means the professors, while British English still favours 'staff.'