From QRZ.Com, the Icom handout, and Part 97 Of The FCC Rules -
Ham Radio Glossary - An overview of amateur radio terms.

Gain
As it applies to antennas, see Antenna Gain

General
The most widely held of U.S. Amateur Radio license. It allows all
amateur radio privileges, except for the 500 kilhohertz of spectrum
reserved for Advanced and Amateur Extra Class licensees.

GMT
See "UTC".

Green Stamp
U.S. dollar bill sent along with a QSL card (instead of an IRC) to
offset postage costs of a return card.

Groundplane
A type of omni-directional antenna.

Ground wave
Electrical wave directly traveling from transmitter.

Grounding
Electrical connection to the radio. Used to disperse harmful build-ups
of static and electrical energy.
--- SBBSecho 3.20-Win32