Merriam-Webster Collegiate Dictionary - solid-state

 adjective  Date: circa 1951  1. relating to the properties, structure, or reactivity of solid material; especially 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 ~ radio