The conversion of a solid to a liquid by the application of heat and/or pressure.
Note:
For a @LT06856@, melting occurs when the three-dimensional periodic structure of a solid collapses to give a liquid-crystal phase in which the molecules have orientational order, but not long range translational order.
Source:
PAC, 1994, 66, 577. 'Definitions of terms relating to phase transitions of the solid state (IUPAC Recommendations 1994)' on page 585 (https://doi.org/10.1351/pac199466030577)