Solid-state physics is the study of rigid matter, or solids, through methods such as solid-state chemistry, quantum mechanics, crystallography, electromagnetism, and metallurgy.
Because its particles are packed close together, a solid is rigid, doesn’t flow, and isn’t easily compressed. A solid is defined as a state of matter with a definite shape and volume.
Solid, one of the three basic states of matter, the others being liquid and gas. A solid forms from liquid or gas because the energy of atoms decreases when the atoms take up a relatively ordered, three-dimensional structure.
Without a break or opening; completely or continuously: The theater was booked solid for a month.