Liquefaction /(lĭk`wē̇*făk"shŭn)/

Liq·ue·fac·tion

Liquefaction

n.
  1. The act or operation of making or becoming liquid; especially, the conversion of a solid into a liquid by the sole agency of heat.
  2. The state of being liquid.
  3. The act, process, or method, of reducing a gas or vapor to a liquid by means of cold or pressure; as, the liquefaction of oxygen or hydrogen. (Chem. Physics)