spreading vertical loads over a sufficient area to ensure the structure will not subside. Lintel – a structural member spanning across the top of an opening. Unlike a beam, a lintel spans a relatively short distance which can be spanned by single block of stone of sufficient depth. Concrete, timber and steel lintels are also used in different types of construction. Pier (architecture) – loadbearing structure similar to a column, but more massive. Truss – a structure spanning in the same way as a beam, but using materials more efficiently by using triangulation to create a rigid structure. Typically timber or steel, used to support a pitched roof. Vault (architecture) – a curved masonry structure spanning in the same way as an arch, forming either a roof or support for a floor above. Wall – a linear structure enclosing the exterior of an area or building, or subdividing an internal space. A wall may be loadbearing or non-loadbearing. Window – an opening in a wall, typically rectangular, providing light and ventilation. Usually but not always glazed. Architectural education Professional requirements for architects – Students undertake specific vocational training in order to qualify as a professional architects. Training typically consists of one or more university degrees and a period of practical experience. In some countries, it is illegal to use the title architect without accredited qualifications. In the United Kingdom the Architects Registration Board exists solely to regulate membership of the profession. In the United States the National Architectural Accrediting Board regulates professional educational programs and the National Council of Architectural Registration Boards is an umbrella organization to recommend model laws, regulations, exams, and to facilitate reciprocity in licensure between different jurisdictions. Architectural education can involve degree types that do not directly result in licensing, such as Bachelor of Science in Architecture, Bachelor of Arts in Architecture, or a research PhD in Architecture. Some of the qualifications specific to architectural licensing include: Bachelor of Architecture (B.Arch.) – undergraduate academic degree designed to satisfy the academic component of professional accreditation bodies, to be followed by a period of practical training prior to professional examination and registration. Master of Architecture (M.Arch.) – professional degree in architecture, qualifying the graduate to move through the various stages of professional accreditation (internship, exams) that result in receiving a license. Doctor of Architecture (D.Arch) – doctoral degree in the field of architecture, that can be completed after