"germ layer." YourDictionary, n.d. Web. 18 October 2018. <http://www.yourdictionary.com/germ-layer>.
germ layer. (n.d.). Retrieved October 18th, 2018, from http://www.yourdictionary.com/germ-layer
Any of three cellular layers, the ectoderm, endoderm, or mesoderm, into which most animal embryos differentiate and from which the organs and tissues of the body develop through further differentiation.