1.) A horizontal member, usually timber bolted or otherwise fixed to the top of a wall to which the roof framing is fixed. 2.) A horizontal member, such as a steel plate fixed to a masonry or concrete wall to carry the end of a beam or to attach a beam to other members. 3.) A horizontal member, either at the top or bottom of a wall frame. Known as top plates or bottom plates. 4.) A board fixed to a vertical surface of a wall to which shoring or props are fixed. Note! when used for the purpose of fixing rafters against a wall then it is known as a Pole Plate.