It does make a difference which term you use, especially in visitor studies and evaluation. Exhibit usually refers to a single element within a group of elements that make up a coherent exhibition. Some museums have exhibits that stand alone and are a group of exhibits, not an exhibition. A room with contemporary art objects chosen with a theme in mind is probably an exhibition. A room with a science topic demonstrated through a variety of elements can be an exhibition. When evaluating visitor responses, it is important to report whether individual elements or whole entities are being considered. ---B. Serrell