This article discusses the concept of ‘Enlightenment’. Many historians of ideas use it in such a vague way that it loses its meaning, for instance to characterize an oppositional attitude no matter when it occurred, or just as a chronological epoch (meaning the whole 18th century). Therefore, it is preferable to have a more distinct definition, based on the French Enlightenment as the main movement. The question of a Swedish Enlightenment is discussed within this framework.