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