- Nuclear fusion is when two or more lightweight atoms join together to form one heavier nucleus, with any energy released due to the conversion being converted into nuclear energy.
An example of nuclear fusion is the process of four hydrogens coming together to form helium.
nuclear fusion definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
the fusion of lightweight atomic nuclei, as of tritium or deuterium, into a nucleus of heavier mass, as of helium, with a resultant loss in the combined mass, which is converted into energy: the principle of the hydrogen bomb