WordNet sense 1 (a system of high tension cables by which electrical power is distributed throughout a region):

power system, power grid

WordNet sense 2 (a network of horizontal and vertical lines that provide coordinates for locating points on an image):

reference grid

WordNet sense 3 (an electrode placed between the cathode and anode of a vacuum tube to control the flow of electrons through the tube):

control grid

WordNet sense 4 (a cooking utensil of parallel metal bars; used to grill fish or meat):

gridiron