In medicine, allo- describes foreign or differing elements, such as nonself tissues from the same species (e.g., in transplants) or geometric isomers in chemistry. It contrasts with auto- (“self”) and can denote opposition or addition in compounds.
Allograft: Transplant from another individual of the same species.
Allergy: Altered reaction to a foreign substance.
Allopathy: Treatment using remedies producing opposite effects.
Alloantigen: Antigen from another individual.
Allogenic: Pertaining to nonself cells from the same species.
greekAllo- originates from Greek állos (ἄλλος), meaning “other,” “different,” or “another,” cognate with Latin alius (“other”) from PIE root al- (“beyond”). [ from prior]