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.
For other uses, see Lumen (disambiguation) . The lumen (symbol: lm) is the SI derived unit of luminous flux, a measure of the total amount of visible light emitted by a source. full sphere has a solid angle of 4Ï steradians, so a light source that uniformly radiates one candela in all directions has a total luminous flux of 1 cd Ã 4Ï sr = 4Ï cdâsr â 12.57 lumens.