freeze, freezing - the withdrawal of heat to change something from a liquid to a solid

liquefaction - the conversion of a solid or a gas into a liquid

natural action, natural process, activity, action - a process existing in or produced by nature (rather than by the intent of human beings); "the action of natural forces"; "volcanic activity"

melt, melting, thaw, thawing - the process whereby heat changes something from a solid to a liquid; "the power failure caused a refrigerator melt that was a disaster"; "the thawing of a frozen turkey takes several hours"

evaporation, vaporisation, vaporization, vapour, vapor - the process of becoming a vapor