Xen- (prefix): Foreign or other. As in:
- Xenoantigen -- An antigen that is found in more than one species.
- Xenograft -- A surgical graft of tissue from one species to an unlike species, genus or family.
- Xenotransplantation -- Transplantation from one species to a foreign one, e.g., the heart transplant from a baboon to Baby Fae in 1984 at Loma Linda University, California.
- Xenotropic virus -- A virus that can grow in the cells of a species foreign to the normal host species.
The origin of "xen-" is from the Late Latin, from Greek, from "xenos" meaning stranger, guest, or host. Xen- and xeno- are variant forms of the same prefix.