The definition of heterogenous refers to something originating outside of the body, or to things that are not from the same source.
Proteins that originate and are found outside of the body are an example of something that would be described as heterogenous.
of different origin; not from the same source, individual, or species
Origin of heterogenoushetero- + -genous
Not arising within the body; derived from another individual or species: a heterogenous bone transplant.
Variant of heterogeneous.