- supernumerary digit
- The condition of having more than the normal number of toes or fingers--called also polydactylia, polydactylism.
Definition from: Merriam-Webster's Medical Dictionary by Merriam-Webster Inc.
- Polydactyly is an abnormality characterized by extra fingers or toes. The condition may be present as part of a collection of abnormalities, or it may exist by itself. When polydactyly exhibits by itself, it is inherited as an autosomal dominant trait.
Definition from: Talking Glossary of Genetic Terms from the National Human Genome Research Institute
See also Understanding Medical Terminology.