Epithelium is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue.
Tissue lining the surfaces of organs in animals
Tissue, which consists of one or more layers of epithelial cells and a basement membrane; it covers the external surface of the body and lines the internal surfaces of the anatomical structures. Examples: simple squamous epithelium, glandular cuboidal epithelium, transitional epithelium, myoepithelium.
A membranous tissue composed of one or more layers of cells which forms the covering of most internal and external surfaces of the body and its organs: internally including the lining of vessels and other small cavities, and externally being the skin.