A genetically engineered organism (GEO) is an organism whose genetic material has been altered using genetic engineering techniques. These techniques, generally known as recombinant DNA technology, use DNA molecules from different sources, which are combined into one molecule to create a new set of genes. This DNA is then transferred into an organism, giving it modified or novel genes.
Genetic engineering can be as simple as enhancing the genes in an organism to preform better then they naturally could, or as radical and advanced as making them preform in ways they never could naturally.