(deu-te-ron') The nucleus of the deuterium atom, consisting of one proton and one neutron, also referred to as heavy water. The nucleus of the deuterium atom is the same as the isotope of hydrogen that has twice the mass of ordinary hydrogen.
The nucleus of a hydrogen-2 (deuterium) atom consisting of one neutron and one proton. A deuteron is considered a subatomic particle with "unit" positive charge.(Basic Science/Radiography/radiationsources/fusion_popup.htm)