an occurrence that involves the production of a union
coalition: the state of being combined into one body
the merging of adjacent sounds or syllables or words
a nuclear reaction in which nuclei combine to form more massive nuclei with the simultaneous release of energy
the combining of images from the two eyes to form a single visual percept
correction of an unstable part of the spine by joining two or more vertebrae; usually done surgically but sometimes done by traction or immobilization
the act of fusing (or melting) together

Fusion is the process that powers the sun and the stars. It is the reaction in which two atoms of hydrogen combine together, or fuse, to form an atom of helium. In the process some of the mass of the hydrogen is converted into energy. The easiest fusion reaction to make happen is combining deuterium (or “heavy hydrogen) with tritium (or “heavy-heavy hydrogen”) to make helium and a neutron. Deuterium is plentifully available in ordinary water. Tritium can be produced by combining the fusion neutron with the abundant light metal lithium. Thus fusion has the potential to be an inexhaustible source of energy.