1. Liquefaction, as by melting by heat. 2. Union, as by joining together, bone fusion. 3. The blending of slightly different images from each eye into a single perception. 4. The joining of two or more adjacent teeth during their development by a dentinal union. 5. Joining of two genes, often neighboring genes. 6. The joining of two bones into a single unit, thereby obliterating motion between the two. 7. The process in which two membranes are joined together.