Bay (architecture)

1. The spaces between posts, columns, or buttresses in the length of a building, the division in the widths being called aisles. This meaning also applies to overhead vaults (between ribs), in a building using a vaulted structural system. For example, the Gothic architecture period's Chartres Cathedral has a nave (main interior space) that is "seven bays long." Similarly in timber framing a bay is the space between posts in the transverse direction of the building and aisles run longitudinally.^[2]
2. If there are no columns or other divisions but there are regularly-spaced windows, each window in a wall is counted as a bay. For example, Mulberry Fields, a Georgian style building in Maryland, United States, is described as "5 bay by 2 bay," meaning "5 windows at the front and 2 windows at the sides".
3. A recess in a wall, such as a bay window.^[2]
4. A division of space such as an animal stall, sick bay, or bay platform.^[2]
5. The space between joists or rafters, a joist bay or rafter bay.^[2]

The Japanese ken and Korean kan are both bays themselves and measurements based upon their number and standard placement. Under the Joseon, Koreans were allocated a set number of bays in their residential architecture based upon their class.

• Architectural elements