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;
\\\"the lumen of the intestine\\\"
造句
用作名詞(n.)
The innermost region of cotton is called lumen. 棉纖維的最內層組織叫內腔。
A former luminance unit equals to one lumen per square foot. 舊制光的亮度單位等于每平方英尺流明。