1. Pertaining to one body in respect of another, or of various bodies in respect to each other, that which is diverse in kind or nature, of completely different characters; incongruous; foreign: Jack found out that a heterogenous mixture was one that consisted of two substances that did not merge, like water and oil.
2. Relating to something that didn't originate inside the body: Sam learned that a heterogenous skin graft was one that did not come from the same source, individual, or species