1. Relating to a disease that has originated outside the body; heterogenic: In class Judy learned that environmental pathogens were microorganisms that spent part of their lives outside the human body, but after entering a person's physical structure, caused heterogenetic illnesses with determinable recurrences.
2. Pertaining to an abnormal organic growth: Jane read that heterogenetic alterations in the developments of living things was also termed abiogenesis.