1. The outermost body layer of an animal, characteristically comprising a layer of living cells—the epidermis—together with a superficial protective coat, which may be a secreted hardened cuticle, as in arthropods, or dead keratinized cells, as in vertebrates (see skin).

2. The outer protective covering of a plant ovule. It is perforated by a small pore, the micropyle. Usually two integuments are present in angiosperms and one in gymnosperms. After fertilization the integuments form the testa of the seed.