[solid-state] adj (ca. 1951) 1: relating to the properties, structure, or reactivity of solid material; esp: relating to the arrangement or behavior of ions, molecules, nucleons, electrons, and holes in the crystals of a substance (as a semiconductor) or to the effect of crystal imperfections on the properties of a solid substance "~ physics"
2. a: utilizing the electric, magnetic, or optical properties of solid materials "~ circuitry" b: using semiconductor devices rather than electron tubes "a ~ stereo system"