A belt course, also called a string course or sill course, is a continuous row or layer of stones or brick set in a wall. Set in line with window sills, it helps to make the horizontal line of the sills visually more prominent. Set between the floors of a house, it helps to make the separate floors distinguishable from the exterior of the building. The belt course often projects from the side of the building. Georgian architecture is notable for the use of belt courses.