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.
The lumen (lm) is an international standardized measurement unit that tells you how much total light is emitted by an LED or other kind of light source. In more technical terms, it is a measure of luminous flux.