(xenograft) The transplant of an organ, tissue, or cells to an individual of another species.

(xenotransplantation) Procedures in which live cells, tissues, or organs derived from one species are transplanted, implanted, or infused into another species; includes those procedures from an animal into a human or from one animal into another; also includes procedures in which human body fluids, cells, tissues, or organs are removed from the body, come into contact with live animal cells, tissues, or organs, and are then placed back into a human patient; this definition is based upon the DHHS definition; where appropriate, index donor and recipient species.

(xenotransplantation) The transfer of cells, tissues, or organs from a donor into a recipient of another species.

(transplantation, heterologous) Transplantation between animals of different species.

Xenotransplantation involves the transplantation of nonhuman tissues or organs into human recipients. The concept was pioneered a century ago, when transplanting human organs was considered ethically controversial.