mucous Syllabification: (mu·cous)Pronunciation: /ˈmyo͞okəs/Definition of mucous adjective relating to, producing, covered with, or of the nature of mucus. Derivatives mucosityPronunciation: /ˌmyo͞oˈkäsətē/ noun Origin: mid 17th century: from Latin mucosus (see mucus)mucous in other Oxford dictionaries Definition of mucous in the British & World English dictionary