Genetics includes the study of genotypes, phenotypes and the mechanisms of genetic control between them. Genetic terms describe the processes, genes and traits with which genetic phenomena are described and examined. The genetic process terminologies are thoroughly discussed in the previous chapters. Therefore, in this chapter, we will only list the terms for genetic processes and concepts in Appendix I (a general genetic glossary), and concentrate the discussion on pig gene and trait terminologies (Appendix 10; a glossary for pig diseases and defects is also included (Appendix III).