Google's Gmail Web-based email service runs on the Internet Message Access Protocol system, but it also offers Post Office Protocol mail server access.
Definition of LUMEN. 1. 2. : the bore of a tube (as of a hollow needle or catheter). 3. : a unit of luminous flux equal to the light emitted in a unit solid angle by a uniform point source of one candle intensity.
Lumen is the SI unit of the luminous flux, which is a measure of the total amount of visible light emitted by a source. It is the perceived power of the light from a source.umen and Lux are two photometric units in the SI system of units. They are closely related to each other and, in simple language, measure how bright a light source appears in two different contexts. These measurements are important in light sources and other cases where the intensity of the light plays a role.