A luminous term referring to the channel within a tube such as a blood vessel or to the cavity within a hollow organ such as the intestine. Lumen is a luminous term because it is Latin for light, including the light that comes through a window. When a hollow organ is cut across, you can see light through the space that has been opened. So the word [..]

The cavity or channel within a tube or tubular organ such as a blood vessel or the intestine.

[L. light] The cavity of a tubular structure, such as endoplasmic reticulum or a blood vessel.

  An empirical measure of the quantity of light. It is based upon the spectral sensitivity of the photosensors in the human eye under high (daytime) light levels. Photometrically it is the luminous fl [..]

Any opening in an organ

The space in the interior of a tubular structure, such as an artery or the intestine.

opening, e.g. of a blood vessel through which blood flows, or in a gland or organ.

unit of luminosity, 1897, coined in French 1894 by French physicist André-Eugène Blondel (1863-1938) from Latin lumen "light" (n.), which is related to lucere "to shine" (see light [..]

The cavity inside a tubular or hollow organ (blood vessel, intestine, uterus). Example: the lumen of the dog's ventricle was virtually filled with heartworms.

A measurement of    the visible illumination emitted by a light source.

A unit of measurement of Incident light. Lumens, like Lux, flux, candela, Foot Candles, foot lamberts, and Watt/seconds, were created by scientists and engineers to confuse artists.

A measurement of light output; refers to the amount of light emitted by one candle that falls on one square foot of surface located at a distance of one foot from the candle.

measurement of light output: One lumen is equal to the amount of light emitted by one candle that falls on one square foot of surface located one foot away from one candle.

(loo´men) The space within a tubular structure through which a substance passes. lung

The cavity of a tube or organ. lung

is the opening area of the inside of a cylinder, or the unit of luminous flux.

inside of a tube (pop)

The channel within a tubular structure.

Cavity of a tube or hollow organ.

The amount of light that is spread over a square foot of surface by one candle when all parts of the surface are exactly one foot from the one candle light source.

A measurement of light output. One lumen equals the amount of light falling on a one square foot area located one foot away from a single candle.

Is the unit of measurement of luminous flux which is the perceived power of light.

The unit of luminous flux; the luminous flux on a unit surface all points of which are at unit distance from a point source of one candle:

lumen ; lm

The hollow part of a tube, like a blood vessel, or the cavity in a hollow organ.

 - Standard unit of measure for light flux or light energy. Lamp light output is measured in Lumens.

The amount of light passing through an area per second. The lumen is defined in terms of the light falling on a unit area at a unit distance from a liht source of luminous intensity of one candela.

N light; lamp| torch; eye (of a person); life; day| daylight

Measure of Light output

the lumen is a unit of luminous flux, as defined in terms of the candela, which is the foundation unit for the measurement of visible light.

The amount of light passing through an area per second. The lumen is defined in terms of the light falling on a unit area at a unit distance from a light source of luminous intensity of one candela.

An international unit (SI) of measurement used to describe the amount of light that a light source produces or emits.

The unit of measure for the light energy which flows in air. The total light output from electric sources is expressed in lumens. A uniform source of one candlepower placed in a sphere emits 12.57 lum [..]

Unit of luminous flux

Unit of luminous flux; the flux emitted within a unit solid angle by a point source with a uniform luminous intensity of one candela.

A lumen (abbreviated as lm) is a unit that measures the visible power output of a light.  While watts measure the power the bulb needs, lumens measure the visible light that the bulb generates.

A lumen is a measure of the amount of visible light emitted by a light source.

the luminous flux of light produced by a light source that emits one candela of luminous intensity over a solid angle of one steradian. Read more.

the channel within a tube such as a blood vessel or the intestine.

The amount of light cast upon 1 square foot of the inner surface of a hollow sphere of 1-foot radius with an international candle in its center.

A lumen (lm) is the International System of Units (SI) measurement for luminous flux (brightness). It is defined as: the amount of light emitted when considering a solid angle of one steradian (sr), f [..]

A unit of luminous flux, equal to the flux through a unit solid angle (steradian) from a uniform point source of 1 cd or 1 FC (foot candle) per sq. foot.

The cavity or channel within a tube or tubular organ such as a blood vessel or the intestine.

In biology, a lumen refers to the space inside of a tubular structure such as the oesophagus, arteries, veins or intestines.

the open inner space of a tube, as in a blood vessel, needle, or catheter.

In biology, a lumen refers to the space inside of a tubular structure such as the oesophagus, arteries, veins or intestines.

The cavity or channel within a tube or tubular organ.

The volume enclosed by the endoplasmic reticulum or the mitochondrial inner membrane; the interior space of a tubular organ such as a blood vessel.

The lumen (symbol: lm) is the SI unit of luminous flux, a measure of the power of light perceived by the human eye.

The derived unit of luminous flux in the International System of Units; it is the luminous flux emitted within unit solid angle (1 steradian) by a point source having a uniform luminous intensity of 1 [..]

A unit measurement of the rate at which a lamp produces light. A lamp's light output rating expresses the total amount of light emitted in all directions per unit time. Ratings of initial light output provided by manufacturers express the total light output after 100 hours of operation.

A unit measurement of the rate at which a lamp produces light. A lamp's lumen output rating expresses the total amount of light the lamp emits in all directions per unit time.

the hollow area within a tube.