Lightingglossary
45 terms with their symbols and units.45 terms with their symbols and units. Short enough to check in the middle of a meeting, clear enough to decide on.
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45 terms
A2 terms
B3 terms
Beam AngleThe width of the angle over which a fixture spreads its light. A narrow beam (15–24°) is used for accent, a wide beam (60°+) for general lighting.BinningThe grouping of LEDs by color and brightness consistency. Tight binning ensures adjacent fixtures appear in the same tone.BollardA short, ground-rising outdoor lighting post used on walkways and landscapes. It usually carries a high IP rating.
C4 terms
CandelacdThe unit of luminous intensity; it measures how concentrated a source's light is in a given direction. It defines the focal power of spots and projectors.cdCircadian LightingLighting that mimics daylight's changing color and intensity to support the human biological rhythm. It is the basis of human-centric lighting (HCL).Color Consistency (MacAdam)A measure of how consistently different fixtures produce the same tone, expressed by the MacAdam ellipse (SDCM). A low SDCM means consistency invisible to the eye.CRI / RaRaThe Color Rendering Index measures how accurately a light shows colors, on a 0–100 scale. Values of 90 and above are considered high quality.Ra
D4 terms
DALIDigital Addressable Lighting Interface; a digital protocol where each fixture can be addressed and controlled individually. Ideal for large, flexible projects.DimmerA control system for adjusting light intensity. It enables shifting moods through the day and saves energy.DownlightA ceiling-recessed fixture that directs light downward. It gives a clean, minimal ceiling and is common in residential and commercial projects.DriverThe electronic unit that supplies the correct current and voltage to the LED. A fixture's lifespan and flicker-free operation depend largely on driver quality.
I · İ4 terms
IK Impact RatingA code showing a fixture's resistance to mechanical impact (IK01–IK10). It matters in public and outdoor spaces.Illuminance LevelThe amount of light measured on a surface (lux). Whether a space is sufficiently lit is judged by this value.Indirect LightingLight delivered by reflecting off a ceiling or wall rather than directly. It creates a soft, shadow-free, glare-free atmosphere.IP RatingA two-digit code showing a fixture's protection against dust and water (e.g. IP65). The first digit denotes solids, the second water resistance.
L7 terms
LEDLight Emitting Diode; a technology that produces light by passing electricity through a semiconductor. It offers up to 80% energy savings and a very long life compared to incandescent lamps.Linear FixtureA fixture that emits straight, linear light. In architectural lighting, corridors and continuous surfaces, it visually extends a space.LumenlmThe total amount of visible light a source emits in all directions. A fixture's brightness is defined by lumens, not watts.lmLumen Maintenance (L70/L80)Describes how an LED loses brightness over time. L70 is the operating time at which a fixture drops to 70% of its initial lumens (e.g. 50,000 hours).Luminancecd/m²The intensity of light reaching the eye from a surface, measured in candela per square meter (cd/m²). It defines how 'bright' a surface appears.cd/m²Luminous FluxThe total visible light energy a source emits per unit time. Its unit is the lumen; luminous flux is expressed in lumens.LuxlxThe intensity of light falling on a surface, measured in lumens per square meter (lm/m²). It is the core unit for illuminance levels.lx
P3 terms
PendantA decorative and functional fixture hanging from the ceiling. It is ideal over dining tables, lobbies and focal points.Profile LightingRecessed or surface linear lighting created with an LED strip set into an aluminum profile. It emphasizes architecture with a concealed light source.PWMPulse Width Modulation; a dimming technique that adjusts brightness by switching the LED on and off very quickly. If done poorly it can cause flicker.
S3 terms
Shadow and ContrastThe relationship between lit and dark areas. The right contrast adds depth and hierarchy; overly flat light makes a space look two-dimensional.Spot / ProjectorA fixture that focuses light at a narrow angle onto a specific point. It is the core tool of accent and display lighting.SSL (Solid-State Lighting)Lighting technology where light is produced with semiconductors instead of filaments or gas. LED and OLED belong to this class.
T4 terms
Task LightingFocused, stronger lighting for a specific activity (reading, food prep, working). It is added to ambient light at specific locations.Thermal ManagementThe removal of the heat an LED produces via a heatsink. Good thermal design preserves lifespan and light quality.Track SystemAn electrified track on which spot fixtures attach and can be positioned freely. It offers flexible, reconfigurable lighting.Tunable WhiteLighting whose color temperature (e.g. 2700K–6500K) can be adjusted. It shifts from warm to cool through the day for dynamic adaptation.
W4 terms
Wall SconceA wall-mounted decorative fixture directing light up, down or both ways. Used in corridors, stairs and atmospheric lighting.WallgrazingA technique that strikes light close to and at a steep angle against a wall to emphasize texture (stone, brick, concrete). Unlike wallwashing, it accentuates shadows.WallwasherA technique that lights a wall evenly and softly from top to bottom. It visually widens a space and emphasizes surfaces.WattWThe electrical power a fixture consumes. It indicates energy use, not brightness.W
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