relating to the properties, structure, or reactivity of solid material, esp relating to the arrangement or behaviour of ions, molecules, nucleons, electrons, and holes in the crystals of a substance, e.g. a semiconductor, or to the effect of crystal imperfections on the properties of a solid substance

solid-state physics

using the electric, magnetic, or photic photic (involving light) properties of solid materials; not using thermionic valves

a solid-state stereo system