1839, shortening of gridiron or griddle. The city planning sense is from 1954 (hence gridlock). The meaning "network of transmission lines" attested by 1926.
Entries linking to grid
gridiron n.
cooking utensil for broiling over a fire, early 14c., griderne, alteration (by association with iron) of gridire (late 13c.), a variant of gridil (see griddle). Confusion of "l" and "r" was common in Norman dialect. Also a medieval instrument of torture by fire. As the word for a U.S. football field, by 1896, for its lines.
griddle n.
shallow frying pan, early 13c., apparently from Anglo-French gridil, Old North French gredil, altered from Old French graille "grill, grating," from Latin craticula "small griddle" (see grill (n.)). Griddle-cake is from 1783.