cold fusion

noun4

1. •
   Nuclear fusion at or near room temperature.
2. •
   A hypothetical and now discredited form of nuclear fusion involving electrolysis of heavy water.
3. •
   (old-fashioned) Muon-catalyzed fusion
4. •
   A method of synthesizing superheavy elements, where the product nucleus has a relatively low excitation energy of ~10 to 20 MeV.