1. (synodontia) The development of one large tooth from two tooth germs which are in close proximity to each other. It involves the union between the dentine or enamel, or both, of the two developing teeth. Unlike gemination, fused teeth have separate pulp canals. Fusion is often associated with a congenitally missing tooth. See also connation.
2. A surgical procedure in which a joint is removed and the cut ends of the bones are held together with screws or clamps.
3. The uniting or joining together of two or more metals.