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"
例句
用作名词(n.)
The innermost region of cotton is called lumen.棉纤维的最内层组织叫内腔。
A former luminance unit equals to one lumen per square foot.旧制光的亮度单位等于每平方英尺流明。
