solid

Definition: A state of matter in which there is a three-dimensional regularity of structure, resulting from the proximity of component atoms, ions, or molecules and the strength of the forces between them. Solids can be crystalline or amorphous. If a crystalline solid is heated, the kinetic energy of the components increases. At a specific temperature, called the melting point, the forces between the components becomes unable to contain them within the crystal structure. At this temperature, the lattice breaks down and the solid becomes a liquid.