Candela vs. Lumen — What's the Difference?

The candela ( or ; symbol: cd) is the base unit of luminous intensity in the International System of Units (SI); that is, luminous power per unit solid angle emitted by a point light source in a particular direction. Luminous intensity is analogous to radiant intensity, but instead of simply adding up the contributions of every wavelength of light in the source's spectrum, the contribution of each wavelength is weighted by the standard luminosity function (a model of the sensitivity of the human eye to different wavelengths).

The SI unit of luminous flux, equal to the amount of light emitted per second in a unit solid angle of one steradian from a uniform source of one candela.

The SI unit of luminous intensity equal to 1/60 of the luminous intensity per square centimeter of a blackbody radiating at the temperature of solidification of platinum (2,046 K). See Table at measurement.

The central cavity of a tubular or other hollow structure in an organism or cell

In the International System of Units, the base unit of luminous intensity; the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540 × 10¹² hertz and that has a radiant intensity in that direction of 1/683 watt per steradian. Symbol: cd

(Anatomy) The inner open space or cavity of a tubular organ, as of a blood vessel or an intestine.

The basic unit of luminous intensity adopted under the System International d'Unites.

(Biology) The interior of a membrane-bound compartment or organelle in a cell.

The basic unit of luminous intensity adopted under the Systeme International d'Unites; equal to 1/60 of the luminous intensity per square centimeter of a black body radiating at the temperature of 2,046 degrees Kelvin

Abbr. lm(Physics) The SI unit of luminous flux, equal to the amount of light per unit time passing through a solid angle of one steradian from a light source of one candela intensity radiating equally in all directions. See Table at measurement.

(physics) In the International System of Units, the derived unit of luminous flux; the light that is emitted in a solid angle of one steradian from a source of one candela. Symbol: lm.

(anatomy) The cavity or channel within a tube or tubular organ.

(botany) The cavity bounded by a plant cell wall.

(medicine) The bore of a tube such as a hollow needle or catheter.

A unit of illumination, being the amount of illumination of a unit area of spherical surface, due to a light of unit intensity placed at the center of the sphere.

An opening, space, or cavity, esp. a tubular cavity; a vacuole.

A unit of luminous flux equal to the amount of light given out through a solid angle of 1 steradian by a point source of 1 candela intensity radiating uniformly in all directions

A cavity or passage in a tubular organ;