Transferred use of the surname, which probably comes from the medieval English female name Diot, a pet form of Dionysia (see Dennis). It is found mainly in North America, where its increase in popularity after the Second World War was a result of the fame of the American general and president Dwight D. Eisenhower (1890–1969). He was named in honour of the New England philosopher Timothy Dwight (1752–1817) and his brother Theodore Dwight (1764–1846).
English (mainly East Anglia): nickname for a pious and demure man, or an occupational name for someone who worked at a convent, from Middle English nunn ‘nun’ (Old English nunne, from Latin nonna, originally a respectful term of address for an elderly woman. The Latin word probably originated as a nursery term).