Glossary

accessibility A property of design describing elements of the physical environment that allow people with disabilities or special needs to use them with safety and dignity.
active solar-heating system A heating system that uses mechanical means to collect, store, and distribute solar energy.
adaptive reuse Changing the function of a building onto something not intended for the original structure.
alternating current (AC) An electric current that reverses direction at regularly recurring intervals.
ambient lighting Lighting designed to provide a nondirectional, shadowless light level from all sides.
ampere A measure of the actual amount of energy flow or current in an electric circuit.
axonometric projection A paraline drawing having all lines parallel to the three principal axes drawn to scale, but with diagonal and curved lines distorted.
bariatric Relating to or specializing in the treatment of obesity.
beam A rigid structural member designed to carry and transfer transverse loads across space to supporting elements.
brightness The sensation by which an observer is able to discern how much light energy is reflected by a surface.
building envelope The shell of a building, consisting of its exterior walls, windows, doors, and roof, which protect and shelter interior spaces from the exterior environment.
building information management (BIM) A digital representation of physical and functional characteristics of a building that serves as a shared knowledge resource.
chroma The degree by which a color differs from a gray of the same lightness or brightness, corresponding to saturation of the perceived color.
color rendering index (CRI) A measure of a lamp's ability to render color accurately when compared with a reference light source of similar color temperature.
column A rigid, relatively slender structural member designed primarily to support loads applied at its ends along its axis.
compact fluorescent lamps (CFLs) Fluorescent lamp with integral ballast, available in many forms.
complementary hues Those hues directly opposite each other on a color wheel.
computer-aided design (CAD) The use of computer technology for the process of design and design documentation.
conduction Direct transfer of heat from the warmer to the cooler particles of a medium or of two bodies in direct contact.
contract furnishings Furnishings purchased for commercial office spaces under a furniture, furnishings, and equipment (FF&E) contract.
convection Heat transfer due to the circulatory motion of the heated parts of a liquid or gas.
cornice A continuous molding that crowns or horizontally divides a wall.
cove (1) A concave surface at the edge of a ceiling that eliminates the interior angle between the wall and ceiling planes, and (2) A concave molding or trim.
dead loads Static loads acting vertically downward on a structure, including the weight of the structure itself and the weight of building elements, fixtures, and equipment permanently attached to it.
decibel (dB) A unit expressing the relative pressure or intensity of sounds on a uniform scale from zero for the least perceptible sound to about 130 for the average threshold of pain.
direct current (DC) A electric current flowing in one direction only.
ductile Capable of being drawn into wire or hammered thin.
dynamic loads Loads applied suddenly to a structure, often with rapid changes in the size of the force and the point to which it is applied, including earthquakes and the loads caused by winds.
efficacy The measure of the efficiency of a light source in lumens per watt.
elastomers Fibers capable of returning to their original shape after being stretched.
embodied energy The total energy consumption associated with a particular material, from raw material acquisition and manufacturing through transportation to point of use.
emphasis The stress or prominence given to an element in a composition by means of contrast, anomaly, or counterpoint.
ergonomics The application of human factors to design.
evaporation Heat loss due to the process of converting moisture into a vapor.
evidence-based design An approach to design that seeks to create better design outcomes by basing decisions on credible research.
faux finish Any of various techniques intended to imitate natural materials, such as wood graining and marbleizing; the term is often used for any decorative painted finish.
fenestration The design and placement of windows in a building.
figure–ground The relationship between the outline or exterior surface of a shape or form (figure) and the receding part of a visual field against which the figure is seen (ground).
flame retardant chemical A compound that inhibits, suppresses, or delays the production of flames to prevent the spread of fire.
floor plan A drawing representing a section through a building or portion of a building after a horizontal slice is made and the upper part removed.
flutter A rapid succession of echoes with sufficient time between each reflection for the listener to be aware of separate, discrete signals, produced by repetitive reflections off hard surfaces arriving at different times, and perceived as a buzzing or clicking sound.
focal lighting Lighting that offers a contrast in brightness that is directive and creates a sense of depth.
footcandle A unit of illuminance derived from the light produced by a candle at the distance of one foot, equal to one lumen incident per square foot.
form The shape and structure of something, as distinguished from its substance or material.
foundation The substructure that forms the base of a building, anchors it to the ground, and supports the building elements and spaces above.
furniture, furnishings, and equipment (FF&E) Term used in commercial design for office furnishings purchased under contract.
furring Wood strips or metal channels attached to a wall to provide a base for lath or a finish material, or to add an air space to composite construction.
gable The triangular portion of wall enclosing the end of a pitched roof.
galvanic corrosion Deterioration of a metal caused by an electrical current flowing between dissimilar metals through a liquid that conducts electricity.
girder A large primary beam designed to support concentrated loads at isolated points along its length.
glazing The panes or sheets of glass or other transparent material made to be set in frames, as in windows, doors, or mirrors.
golden section Proportion between two unequal parts of a whole in which the ratio between the smaller and greater parts is equal to the ratio between the greater part and the whole.
harmony The consonance or pleasing agreement of elements or parts in a composition.
header (1) A framing member supporting the ends of joists, studs, or rafters to transfer the load to parallel joists, studs, or rafters, and (2) A masonry unit laid horizontally in a wall with its end parallel to the surface.
high-intensity discharge (HID) lamp A lamp that produces light by the discharge of electricity through a metallic vapor in a sealed glass enclosure.
hue The attribute by which we recognize and describe a color, such as red or yellow.
illuminance The quantity of light striking a surface, measured in footcandles or lux.
infiltration The flow of outside air into an interior space through cracks around windows and doors or other openings in the envelope of a building.
interior elevation An orthographic projection of any of the significant interior walls of a building.
joists A series of small, parallel beams for supporting floors, ceilings, or flat roofs.
kerf A groove cut into the edges of a material, such as an acoustical tile, to receive a supporting grid.
laminated glass Two or more plies of glass bonded to an interlayer that retains the fragments if the glass is broken.
lamp (1) A device that produces light; a bulb or tube within a lighting fixture, and (2) Common name for a plug-in lighting fixture, such as a table lamp or floor lamp.
lateral force Any force acting horizontally on a structure.
lath Thin strips of wood or metal attached to framing to provide a substructure for plaster.
lavatory A bowl or basin with running water for washing the face and hands.
line A geometric element that conceptually has only one dimension, length. A line's length visually dominates whatever thickness it must have to be visible.
lintel An arch or a short beam that supports the wall load above an opening and allows compressive stresses to flow around the opening to adjacent sections of the wall.
live loads Loads that change over time, but generally gradually, including the weight of a building's occupants, any mobile equipment and furnishings, and any collected snow and water.
load-bearing wall A wall capable of supporting an imposed load, as from a floor or roof.
lumen A measure of the amount of light emitted by a light source or falling onto a surface, regardless of directionality.
luminance A measure of brightness of a light source or an illuminated surface.
motif A distinctive and recurring shape, form, or color in a design.
multiview drawings A set of related orthographic projections of an object or construction, including plans, elevations, and sections.
natural ventilation Providing fresh air by means of the natural movement of air, rather than by mechanical means.
oblique projection The representation of a three-dimensional object with one principal face parallel to the picture plane, created by projecting parallel lines at angles other than 90 degrees to the picture plane.
off-gassing The vaporization of chemical compounds into surrounding air.
orthographic projection A method of projection in which parallel projectors meet the picture plane at right angles; any element that is parallel to the picture plane remains true in size, shape, and configuration.
paraline drawing A drawing in which parallel lines remain parallel to each other rather than converge, as they do in linear perspective.
partition A non-load-bearing interior wall dividing a room or part of a building into separate areas.
passive solar-heating system A heating system that uses a building's design and the natural flow of heat to collect, store, and distribute solar energy, with minimal use of fans or pumps.
pattern The decorative design or ornamentation of a surface that is almost always based on the repetition of a design motif.
perspective drawing A drawing that represents three-dimensional objects and spatial relationships on a two-dimensional surface as they might appear to the eye.
photovoltaic (PV) Of or related to a technology that uses a solid-state device capable of converting solar energy into electrical energy, such as that employed by a solar panel to produce an electric current when exposed to light.
pigment A finely ground, insoluble substance suspended in a liquid vehicle to impart color and opacity to a coating.
pilaster A shallow rectangular projection from a wall, architecturally treated as a column.
plane A surface generated by a line moving in a direction other than its intrinsic direction. A plane's width and length dominate whatever thickness it must have to be visible.
plenum The space between a suspended ceiling and the floor structure above, or the space below a raised access floor, especially when used for distributing or returning conditioned air.
point A dimensionless geometric element marking a location space. Conceptually, it has no length, width, or depth; commonly manifested as a dot.
polybrominated diphenyl ethers (PBDE) Chemicals used as flame retardants in building materials, furnishings, polyurethane foams, and textiles, which may be associated with fertility problems in humans.
potable Water fit for human consumption.
proportion The relationship of one part to another or to the whole, or between one object and another.
rabbet A channel, groove, or notch cut along or near one edge of a member so that something else can be fitted into it.
radiation Heat energy emitted by a warm body, transmitted through an intervening space, and absorbed by a cooler body, without being affected by air motion or temperature.
reveal A continuous recess that visually separates the meeting of two planes and articulates their edges by the shadow lines they create.
reverberation The persistence of a sound within a space, caused by multiple reflections of the sound after its source has stopped.
rhythm Movement characterized by a patterned repetition or alternation of formal elements or motifs in the same or a modified form.
riser (1) The vertical face of a stair step, and (2) A vertical pipe, conduit, or duct in a utility system.
safety glazing Glazing that meets Consumer Product Safety Commission test requirements, such as tempered glass and laminated glass.
saturation The purity or vividness of a hue; the intensity of a color.
scale A certain proportionate size, extent, or degree, usually relative to some known standard or recognized constant.
section An orthographic projection of an object or structure as it would appear if cut through by a vertical plane to show its internal configuration.
seismic Of, pertaining to, or caused by an earthquake or vibration of the earth.
shade A relatively dark value of a color, produced by adding black to it.
shape The outline or surface configuration of a form or figure, usually with some emphasis on the enclosed area or mass.
shear wall A vertical diaphragm acting as a thin, deep cantilever beam in transferring lateral loads to the ground foundation.
shed roof A roof having a single slope.
skim coat A thin leveling or finish coat of plaster.
slab A horizontal, rigid, usually monolithic plate, such as a reinforced concrete slab.
soffit The underside of an architectural element, such as an arch, beam, cornice, or staircase.
sone A unit for measuring the apparent loudness of a sound.
sound transmission class (STC) A single-number rating of the performance of a building material or construction assembly in preventing the transmission of airborne sound.
specular Reflection on a smooth surface such as polished glass or stone, where the angle of incidence equals the angle of reflection.
stop The projecting part of a doorframe against which a door closes.
structure (1) A stable assembly of elements designed and constructed to function as a whole in supporting and transmitting applied loads safely to the ground, and (2) The organization of elements or parts in a complex system as dominated by the general character of the whole.
substrate Any material that underlies or serves as a base or foundation for another material.
superstructure The structural frame of a building, consisting of columns, beams, and load-bearing walls that support the floor and roof structures.
sustainable design A holistic approach to building design that reduces negative social, economic, and ecological impacts on the environment through conservation and reuse of natural resources, energy, water, and materials.
tempered glass Annealed glass reheated and cooled to increase its resistance to impact and thermal stresses; it breaks into small cubical pieces.
texture The visual and tactile quality of a surface, apart from its color or form; most often used to describe the relative smoothness or roughness of a surface.
tint Lightening a hue's normal value by adding white creates a tint of that hue.
tone An intermediate value of a color between a lighter tint and a darker shade.
transmission loss (TL) A measure of the performance of a building material or construction assembly in preventing the transmission of airborne sound.
tread The horizontal upper surface of a step in a stair, on which the foot is placed.
trompe l'oeil A drawing or painting that uses perspective and shadow to create the illusion of three-dimensional objects.
valance (1) A horizontal board or band used to conceal lighting, and (2) A short, ornamental piece of drapery placed across the top of a window.
value The degree to which a color appears to reflect light, corresponding to the lightness of the perceived color.
vault An arched structure forming a ceiling or roof over an enclosed space.
veiling reflection Reflected glare on a task surface that reduces the contrast necessary for seeing details.
visitability A movement to construct the majority of new homes so that they can be readily lived in and visited by people with impaired mobility.
vitreous Resembling glass in transparency, hardness, brittleness, luster, or imperviousness.
volatile organic compound (VOC) A hydrocarbon compound that evaporates readily; some VOCs are gases at room temperature.
volt Measure of the potential electrical energy flow through a conductor, in response to a difference in electrical charge between two points in a circuit.
volume The extent of a three-dimensional object or the amount of space that it occupies, measured in cubic units.
water closet A fixture consisting of a ceramic bowl with a detachable, hinged seat and lid and a device for flushing with water; also called a toilet.
watt A measure of the power required to keep an electric current flowing.
winder A wedge-shaped tread used in circular, spiral, and turning stairs.
wire glass Flat or patterned glass having a wire mesh embedded into the center of the glass sheet to prevent shattering in the event of breakage or excessive heat.