Select Page



Noun, pl. lumens

1. 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. (

2. 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

Symbol: lm

Noun, pl. lumina

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

The cavity bounded by a plant cell wall. (

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

Word origin: From Latin lumen “light,” related to lucere “to shine”

Struggling in Biology?

Are You Premed?

Confused about the MCAT? Not sure how to prepare? This guide will show you how