[elec.tro-op.ti.cal] or elec.tro-op.tic adj (1879) 1: of or relating to electro-optics
2. a: relating to or being a change in the refractive index of a material due to an electric field "~ effect" b: using or being a material that exhibits electro-optical properties "an ~ crystal"
3: relating to or being an electronic device for emitting, modulating, transmitting, or sensing light -- elec.tro-op.ti.cal.ly adv