Get To Know Your Lighting Terms
Get To Know Your Lighting Terms

Lighting Glossary

Are you ever confused by some of the specialized terms you run into while shopping for lighting? Do you want to clear up the distinction between Art Deco and Art Nouveau? Or dazzle your family and friends with knowledge about possibly the most important element of any space? Here in our lighting glossary, I can help. Read on to become more enlightened about the wide variety of terms used in the world of lighting. This includes electrical terms, material and style terms, information about ceiling fans and more!

Accent Lighting: The local and directional light used to highlight and dramatize artwork, plants, collectibles and special possessions, as well as architectural features and furnishings.

ADA Compliant: Meets requirements set forth by the Americans with Disabilities Act. ADA-compliant fixtures must be used in public circulation areas of commercial and institutional buildings when mounted below 80" from the floor. To be ADA compliant, a wall fixture must extend no more than 4" from the wall.

A Bulb: The shape of a standard household bulb. The A stands for arbitrary.

ALA: Acronym for the American Lighting Association, the trade organization representing lighting designers, manufacturers and retailers. We are proud to be ALA-certified lighting specialists at Lights Online!

Alabaster - Lighting Glossary - LightsOnline.com

Alabaster: A compact gypsum mineral-like stone that creates a warm, rich diffuser of light. Often used in European or high-end chandeliers, alabaster is unique in its tint and the character of its veining. No piece of stone is identical to another. The bowl pendant seen at right has an alabaster shade.

Aluminum: Aluminum is a pure metal. It forms and finishes easily. It can be dyed to a brass-like finish, but it lacks the depth and luster of real brass.

Ambient Lighting: General lighting that provides overall illumination for atmosphere, safety, security and the performance of simple activities. Ambient lighting also provides background brightness that reduces excessive contrast from localized task or accent lighting.

Anodized Aluminum: Aluminum that is chemically treated to prevent the fixture from corroding and to protect the finish.

Architectural Fixture: Refers to built-in fixtures in a residence or building, like recessed lighting in the ceiling or strip lights in a cove.

Art Deco: An industrial aesthetic used in lighting design that harkens back to the 1920s. Art Deco is typified by geometric forms, lavish decoration and vivid, high-contrast colors.

Art Glass: Glass creations individually produced by a glass artisan. Art glass may fuse several types of glass or incorporate pigments and other types of materials to deliver one-of-a-kind patterns.

Art Nouveau: A highly ornate style popular in early 20th Century art and architecture. Art Nouveau lighting is typically characterized by intertwined organic forms, like stems and flowers.

Ballast: An electrical device for fluorescent light sources that is typically located in the fixture. The ballast provides the high initial current that starts the fluorescent lamp (called "striking an arc") and then delivers the correct current to maintain the arc in the lamp. Ballasts must match the lamp type and wattage to assure proper operation.

Bearings: Ceiling fan bearings separate the moving part of the motor from the housing around it and reduce friction and wear. Ceiling fan bearings are precisely formed spheres of hard metal or composite that revolve as the motor spins against them. High-quality bearings contribute to quiet, vibration-free operation and long life.

Beveled Glass: Glass with edges that are cut to an angle to add depth and glitter.

Blade Pitch: The angle of the blades on a ceiling fan. This helps determine the efficiency of the air movement produced by the ceiling fan.

Blade Sweep: Diameter of the ceiling fan, from blade tip to blade tip.

Blown Glass: Blowing glass permits a hollow form that is almost fully rounded, where the opening at the bottom is smaller than the diameter. Hand blown glass is created by artisans who blow air into a molten balloon of glass. The artisan's skill determines the shape and texture of the outcome. Expect the small variations in form that distinguish hand-made materials.

Brass - Lighting Glossary - LightsOnline.com

Brass: An alloy of zinc and copper. Brass forms and polishes easily, but unless it's protected by a lacquer finish, it will tarnish. Solid brass means the fixture is made entirely of brass, rather than a brass-plated metal. The pendant pictured on the left has an aged brass finish.

Cased glass: Glass with a layer of clear glass fused to a layer of opal or other tinted glass.

Chrome: Chrome takes a high-lustrous polish. It is plated to steel to make flat parts and to brass or bronze for cast parts. A softly brushed chrome finish simulates stainless steel.

Circuit: A closed path of electricity. A circuit in the home includes a breaker or fuse, the wiring and the load.

Circuit Breaker: A circuit breaker or fuse protects a circuit from being overloaded.

Color Rendering: The presence or absence of color in a light source, which determines how it renders light. Therefore, two sources of the same color temperature will render objects differently, depending on the spectrum of color that makes up each source. For example, colors appear different under a cool white fluorescent light than they do outdoors at five in the afternoon, although the color temperature is similar.

Color Rendering Index (CRI): Measures how well a lamp illuminates an object's color tones. The index runs from 0 to 100 and a perfect 100 score is daylight.

Color Temperature: Refers to how warm (reddish) or cool (bluish) a tint of white appears. Color temperature is a number that quantifies the appearance of light with the terms "warm" and "cool," which refer to subjective experiences like a warm flame or a cool winter sky. Color temperature is measured in degrees Kelvin.

Color temperature comparisons by Yerocus on Wikimedia Commons

Contemporary: Contemporary design refers to products designed to be "of the current time." As current styles change, contemporary design sometimes becomes less "modern" in feel. Like fashion in clothing, fashion in lighting (and all home furnishings) is cyclical.

Crystal: Clear glass.

Decorative Lighting: Lighting that is designed to be a focal point, adding a festive sparkle and appealing glow to a room to enhance decor. Functional lighting can also be decorative.

Diffusion: Tinted and gently textured materials, such as cloth shades and specialty glass. Diffusion softens light by spreading it out, making it more comfortable.

Downlight: When illumination is projected down toward the ground.

Downrod: The ceiling fan downrod is the pipe that suspends the fan from the ceiling box. Most fans include a very short downrod, but other lengths and extenders are available so you can hang the fan at the desired height. Pendants, chandeliers and other fixtures may also have downrods.

Efficiency: Relates light output (lumens) to the electric power required to produce it (watts). Measured as lumens per watt. Light source efficiency is the best measure of the lifecycle cost.

European: Refers to traditional lighting styles that are elaborate, "heavy" in appearance and crafted of fine materials like crystal, alabaster and bronze.

Etched glass - LightsOnline.com

Etched Glass: Etched glass is bathed in acid, which eats the surface to produce a light diffusing texture. The sconce shown at left has etched glass.

Finish: The way a fixture is polished, painted, lacquered or chemically treated.

Fluorescent: Light source that creates light through a 3-step process. First, the lamp generates an arc (electric current through gas). Then, the arc stimulates the gas inside the tube, which emits ultraviolet energy. This in turn stimulates a phosphor coating insure the lamp. Fluorescent lights create light very efficiently and last a long time (up to 30,000 hours), thus dominating commercial, industrial and institutional applications. Due to improvements in color rendering, fluorescent sources are becoming more popular in homes.

Foot-candles: A measurement of how much light falls on a surface. One lumen of light falling on one square foot equals a single foot-candle.

Halogen: Type of incandescent lighting offering longer life, higher efficiency and a whiter light. The lamp contains halogen gas that recycles tungsten, helping to keep the bulb clean and maintain lumen output.

Incandescent Light: The most common source of light. Incandescent bulbs create illumination by causing a filament to glow by heating it with electricity.

Junction Box: A metal or plastic enclosure in which wires are joined or spliced. Surface-mounted fixtures attach to junction boxes. Junction boxes must be accessible.

Lamp: You might think of a lamp as something you put on a table to brighten it up, but sometimes 'lamp' is also used to refer to a light bulb. (In that case, a lamp like a table or floor lamp would be referred to as a 'portable'.)

Lead Crystal: Crystal that contains at least 24% lead oxide. The lead content softens the glass, permitting very precise cutting and smooth polishing. Fine lead crystal that is hand-cut, sharply faceted, pure and highly polished refracts light with brilliance and clarity.

LED (Light Emitting Diode): A form of solid state lighting that is at the leading edge of evolving lighting technology. Known for longevity and versatility, companies are also starting to produce LED bulbs for residential applications.

Light Kit: Ceiling fan light kits are accessories that attach to the bottom of a fan, providing a choice of lighting options.

Line Voltage Bulb (or lamp): Operates directly off the household current at the North American standard of 120 volts. Most incandescent light sources for general and decorative lighting are line voltage. Available in 120 volt or 130 volt (the latter is typically used in commercial applications). You can dim line voltage bulbs lights with basic, inexpensive dimmers.

Low Voltage Bulbs (or lamps): Operates at a reduced voltage, most often at 12 volts. A transformer is required as part of the fixture or the current to change the 120 volt household current to the lower 12 volts. The chief benefit is the ability to make the light source very small and deliver a precise beam of light. Low voltage systems are most often used in accent and landscape lighting.

Lumens: The raw quantity of light given by a light source. All common electrical sources are rated in lumens. This is what determines how bright a light will be, not wattage.

Mission: Lighting style defined by simple, geometric angles and handcrafted elements. Mission style is an outgrowth of the Arts & Crafts movement.

Modern: Modern light fixtures tend to have clean lines, forms that follow the intended function and new materials. Many of the fixtures we think of as modern have their inspiration in the International Style of the 1930s-1950s.

Motor: The heart of every ceiling fan is its motor. An electric motor converts electric energy into mechanical energy into mechanical energy or motion. Most fan motors can be reversed to change the airflow pattern. The quality of a ceiling fan is heavily determined by the quality of the motor. There are 2 types of fan motors. The most common is called a "pancake" due to its flat shape. Pancake motors are described by size: diameter x height. "Stacked" motors with a more elaborate construction are used in some premium fans.

Opal Glass: Opal glass is tinted white throughout and has a milky white translucence that diffuses light.

Oxidized: Rusted.

Patina: The natural and beautiful effect of age or exposure to the elements. Patina can be simulated, too.

Pin-Based Bulb: Type of compact fluorescent light bulb in which the ballast is separated from the bulb and housed in the fixture.

PAR bulb - LightsOnline.com

PAR Bulb: Parabolic-shaped hard glass with an aluminized coating and a molded glass lens. Low voltage PAR lamps are popular for sophisticated accent lighting and landscape lighting. Their thick glass makes them ideal for outdoor use. Onthe left is an example of a PAR bulb.

Reflectance: The quality of surfaces that determines how much light is reflected. Reflectance is shown as a percentage. A black painted surface, for example, reflects less than 5% of the light striking it, whereas white paint reflects up to 90%.

Reflectorized Bulb: Light bulbs that have a glass envelope shaped and finished to direct light into a beam. Primarily used for accent and task lighting, as well as throwing light from long distances, like in a high ceiling.

Sand Blasted Glass: Glass diffused with a light texture that is coarser than etching. Bead blasting abrades the surface of the glass with larger particles for a still rougher texture.

Scavo Glass: Glass that is "antiqued" by applying hot abrasives to create a roughly textured finish that suggests great age.

Sconce: A wall-mounted light fixture.

Screw-Based Bulb: Type of bulb with a screw-on base, compatible with most fixtures. Many LED and compact fluorescent bulbs have screw bases and can fit light fixtures that are designed to accept incandescent bulbs.

Seeded Glass: Seeded glass has tiny air bubbles in it that refract the light to create visual interest. Seeded glass can also have an antiqued look because old glass often had impurities in it. An example of seeded glass is on the right.Seeded glass - LightsOnline.com

Task Lighting: Provides the higher level of localized light needed for specific visual activities, such as reading, hobbies, workshop repairs, sewing, grooming, and food preparation.

Tiffany: Lighting designs with brightly colored glass or other material forming a mosaic pattern. Tiffany lighting was named for renowned American artist Louis Comfort Tiffany.

Tinted Glass: Tinted glass is pigmented, like opal glass. This produces color throughout that will not chip or peel.

Traditional: Traditional light fixtures have origins in a specific historical period. In North America, traditional light fixtures most often reflect styles from the 18th and 19th centuries, themselves inspired by Greek and Roman design.

Transformer: Device that is required to convert one level of voltage to another. You need a transformer with low-voltage light fixtures.

Transitional: Transitional light fixtures are compatible with a number of decor styles, from traditional to contemporary.

Uplight: When illumination is projected up toward the ceiling.

Voltage: Measures the electrical "pressure" that creates a current. Electric utilities distribute power efficiently over long distances at high voltage. Transformers reduce the voltage to safe and practical levels for household use. Most lighting and household appliances operate at 110-120 volts. Heavy appliances use 220-240 volts. Low voltage is defined as less than 30 volts. Most low voltage lighting operates at 12 volts.

Voltage Drop: A negative effect that occurs as an electrical current travels over extensive lengths of relatively small conductors. Voltage drop will dim the lights at the end of the wiring compared to the rest of the circuit.

Wall Lighting: Light directed onto vertical surfaces that has the ability to make a room seem larger. Also sometimes called "wall washing," this technique can help bring textures to life or illuminate a group of paintings.

Wattage: The power required to operate electric lighting is measured in watts. The wattage of a light bulb does not tell you how much light it produces. Instead, wattage refers to how much power the light will consume and therefore how expensive it will be to operate.

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