1911 Encyclopædia Britannica/Basement

​BASEMENT, the term applied to the lowest storey of any building placed wholly or partly below the level of the ground. It is incorrectly applied to the ground storey of any building, even when, as for instance in the case of Somerset House, London, the ground floor is of plain or rusticated masonry, and the upper storey which it supports is divided up and decorated with columns or pilasters.