(ek′tō dʉrm′, -tə-)
- the outer layer of cells of an animal embryo, from which the nervous system, skin, hair, teeth, etc. are developed
- the layer or layers of cells composing the skin, nervous system, etc. in all animals except protozoans and sponges
ecto- + -derm
See ectoderm in American Heritage Dictionary 4
- The outermost of the three primary germ layers of an embryo, from which the epidermis, nervous tissue, and, in vertebrates, sense organs develop.
- The outer layer of a diploblastic animal, such as a jellyfish.
- ecˌto·derˈmal, ecˌto·derˈmic adjective
Learn more about ectoderm