Interolog

An Interolog is a recently introduced term used in the fields of System Biology and Bioinformatics.

Definition
Consider two different human protein molecules A and B that interact, i.e. bind to each other. If you would look for homologous proteins to A and B (homologs = proteins that are similar in their aminoacid sequence) in another organism (e.g. a dog), we might find the dog proteins A' and B', where A' is homologous (similar in sequence) to A and B' is homologous to B. Now, we would call the pair A' and B' an interolog of A and B if (and only if!) A' and B' also bind to each other.

Thus, interologs could be described as a resembling pair of protein-protein interactions (e.g. A-B and A'-B'), which can be observed parallelly in two different organisms.