- 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
Origin of ectodermecto- + -derm
- 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.
- ec′to·der′mal, ec′to·der′mic