Chimera: In the context of multicellular animals, a chimera is an individual that contains cells derived from multiple parents. In a general sense, “chimera” means something with a mixed constitution. In Greek mythology, a chimera is a monster that has a lion's head, a goat's body, and a serpent's tail. See also chimeric proteinplugin-autotooltip__default plugin-autotooltip_bigChimeric protein: a protein that is the result of artificially joining together parts of two or more unrelated proteins. Also called a fusion protein..