1. (in perspective drawing) the theoretical horizontal plane receding from the picture plane to the horizon, beginning at the level of the base line.
2. Elect.a ground plate or an underground mesh of radial wires connected to a vertical antenna (ground' plane" anten"na) that is grounded in order to provide suitable radiation characteristics.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.