cold fusion
From Longman Dictionary of Contemporary Englishcold fusionˌcold ˈfusion noun [uncountable] a type of nuclear fusion (=the joining together of the centre of two atoms, which releases energy) which some scientists believe can happen at extremely low temperatures, but which other scientists believe is impossibleExamples from the Corpuscold fusion• Fleischmann and Pons thought that they could achieve cold fusion by another route.• That is what happened when the news of cold fusion erupted.• The cold fusion controversy provides a vivid illustration.