The architectural space between two load-bearing walls, two column alignments (porticoes), or between a wall and adjacent aligned columns is called a bay.
This space also refers to the naves or corridors of certain buildings, which give access to side rooms, as is the case with each of the galleries, or pandas, of a cloister. Constructively, it is each of the main parts into which the plant of a building is divided. The first bay is called the one located closest to the façade, being numbered correlatively towards the interior of the building.
The simplest architectural composition is the typology made up of the juxtaposition of bays. In this form of composition, the communication of the enclosures is established by opening holes in the walls; holes are also used to ventilate and illuminate the rooms. The compartmentalization of the bays is usually carried out by partitioning.