epithelium

== English == === Etymology === From New Latin epithēlium. By surface analysis, epi- +‎ thel- +‎ -ium. === Pronunciation === (UK) IPA(key): /ˌɛpɪˈθiːlɪəm/ Rhymes: -iːliəm === Noun === epithelium (countable and uncountable, plural epitheliums or epithelia) (anatomy) 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. Synonym: epithelial tissue ==== Hyponyms ==== ==== Derived terms ==== ==== Related terms ==== thelarche thelion thelitis thelium ==== Translations ==== ==== See also ==== epidermis == Latin == === Etymology === Introduced by Frederik Ruysch in the 18th century, originally referring to the covering of small "nipples" of tissue on the lip. Initially a first-declension noun epithēlia, from Ancient Greek ἐπι- (epi-, “on, atop”) +‎ Ancient Greek θηλή (thēlḗ, “nipple”) +‎ -ia; the nominative singular was later reinterpreted as a second-declension neuter plural. === Pronunciation === (Classical Latin) IPA(key): [ɛ.pɪˈtʰeː.li.ũː] (modern Italianate Ecclesiastical) IPA(key): [e.piˈtɛː.li.um] === Noun === epithēlium n (genitive epithēliī); second declension (New Latin, anatomy) epithelium ==== Declension ==== Second-declension noun (neuter). === References === “epithelium, n.”, in OED Online ⁠, Oxford: Oxford University Press, March 2024.