1640s (Browne, from Gilbert's Modern Latin), from electric (q.v.) + -ity. Originally in reference to friction.
Electricity seems destined to play a most important part in the arts and industries. The question of its economical application to some purposes is still unsettled, but experiment has already proved that it will propel a street car better than a gas jet and give more light than a horse. [Ambrose Bierce, "The Cynic's Word Book," 1906]