A GMO is a genetically modified organism or plant. This organism or plant's genetic composition has been altered through genetic engineering. You can learn more at http://www.nongmoproject.org/learn-more/.
Genetically Modified Organism-- they are plants or other organisms that have a different genetic composition than they originally or were supposed to have. (GMO's are the reason High Fructose Corn Syrup is bad--90% of corn processed is a GMO, please correct me if I'm wrong). GMO's are all over the place. Stick with organic foods and the fish that doesn't have three eyes.