BAY- An opening in a wall; a horizontal area division of a building, usually defined as the space between two columns or piers.
BEAM- A horizontal load-supporting member of a building which directly supports a floor; may be of wood steel, or concrete; transmits load horizontally to vertical columns or bearing walls. Normally beams are larger and are spaced further apart than "joist."
BEARING WALL- A wall which supports any vertical load in a building (such as floors, roofs, joist, beams or girder) as well as its own weight.
BEARING- The area of contact between a structural member (beam, girder, footing) and its underlying support (column, bearing wall, load bearing ground).