1. The compatibility of a donated organ or artificial limb with the living tissue into which it is implanted or with which it is brought into contact. Incompatibility leads to toxic reactions or immunological rejection.
2. Being harmonious with life; that is, not having toxic or injurious effects on biological functions.
3. The capability of coexistence with living tissues or organisms without causing harm: "Artificial joint adhesives must have biocompatibility with bone and muscle or they will result in sever damage."