back-of-the-envelope

== English == === Etymology === A reference to a calculation or an idea that occurs to one being jotted down on an available scrap of paper, such as the back of an envelope. === Pronunciation === (Received Pronunciation) IPA(key): /ˌbæk‿əv ðiː ˈɛnvələʊp/, /-ˈɒnvələʊp/, /-ˈɒnvləʊp/ (General American) IPA(key): /ˌbæk‿əv ði ˈɛnvəˌloʊp/, /-ˈɑnvəˌloʊp/, /-ɛnvəˌlop/ Hyphenation: back of the en‧vel‧ope === Adjective === back-of-the-envelope (idiomatic, informal) Especially of a calculation, estimation, or other reasoning, or an idea: approximate, rough, simplified. [from 20th c.] Synonyms: (UK) back-of-the-fag-packet, (US) back-of-the-napkin ==== Alternative forms ==== back-of-an-envelope ==== Translations ==== ==== See also ==== napkin math === References === === Further reading === back-of-the-envelope calculation on Wikipedia.Wikipedia “back-of-the-envelope, adj.”, in Merriam-Webster Online Dictionary, Springfield, Mass.: Merriam-Webster, 1996–present.