Epithelium

[ep-uh-thee-lee-uh m] /ˌɛp əˈθi li əm/

noun, plural epitheliums, epithelia
[ep-uh-thee-lee-uh] /ˌɛp əˈθi li ə/ (Show IPA). Biology.
1.
any animal tissue that covers a surface, or lines a cavity or the like, and that, in addition, performs any of various secretory, transporting, or regulatory functions.
/ˌɛpɪˈθiːlɪəm/
noun (pl) -liums, -lia (-lɪə)
1.
an animal tissue consisting of one or more layers of closely packed cells covering the external and internal surfaces of the body. The cells vary in structure according to their function, which may be protective, secretory, or absorptive
n.

1748, Modern Latin (Frederick Ruysch), from Greek epi “upon” (see epi-) + thele “teat, nipple” (see fecund). Related: Epithelial.

epithelium ep·i·the·li·um (ěp’ə-thē’lē-əm)
n. pl. ep·i·the·li·ums or ep·i·the·li·a (-lē-ə)
Membranous tissue composed of one or more layers of cells separated by very little intercellular substance and forming the covering of most internal and external surfaces of the body and its organs.
ep’i·the’li·al adj.
epithelium
(ěp’ə-thē’lē-əm)
Plural epithelia
The thin, membranous tissue that lines most of the internal and external surfaces of an animal’s body. Epithelium is composed of one or more layers of densely packed cells. In vertebrates, it lines the outer layer of the skin (epidermis), the surface of most body cavities, and the lumen of fluid-filled organs, such as the gut or intestine.

epithelial adjective