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.
A Lumen (or luminous flux, or Lm) is the total number of packets of light (or quantity of light output) produced by a light source. For example, a 100-watt incandescent lamp emits about 1300 lumens. Read more here.