In American archaeology this term refers to styles of artefact, assemblages of tools or other items of material culture, architectural styles, economic practices, or artistic styles that last longer than a phase or the duration of a horizon. The idea of a tradition implies a degree of cultural continuity even if there are local or regional patterns in the archaeological material. The term was defined in its modern usage by G. Willey and P. Phillips in 1955, although the word had been widely used in a variety of ways before that time, and continues to be variously and less specifically applied. The Arctic Small Tool Tradition is a good example of the way in which the term applies: persistent technological or cultural patterns identified by characteristic artefact forms. These persistent forms outlast a single phase and can occur over a wide area.