What does the prefix xeno- indicate?

The prefix "xeno-" is derived from the Greek word "xenos," which means "foreigner" or "stranger." In medical terminology, it typically indicates something that is foreign or coming from outside an organism. This can refer to foreign tissues, cells, or organisms, such as in the context of xenotransplantation, which involves transplanting organs from one species to another. Understanding the significance of "xeno-" is important in various fields of medicine, including immunology and transplant biology, where the body's response to foreign substances is a critical factor.