1. an occurrence that involves the production of a union
2. a nuclear reaction in which nuclei combine to form more massive nuclei with the simultaneous release of energy
3. the state of being combined into one body
4. the merging of adjacent sounds or syllables or words
5. the combining of images from the two eyes to form a single visual percept
6. correction of an unstable part of the spine by joining two or more vertebrae; usually done surgically but sometimes done by traction or immobilization