merveille du jourPronunciation: /mɛːˌveɪ d(j)uː ˈʒʊə/Definition of merveille du jour noun a European moth with greyish-green coloration that camouflages it when at rest on lichen-covered bark. Dichonia aprilina, family Noctuidae Origin: late 19th century: from French, literally 'wonder of the day'
