Pronunciation IPA (key): /ˈmɑrʃənɨs/ or /mɑrʃəˈnɛs/ Noun Singular marchioness Plural marchionesses (countable) A marchioness is the wife of a marquess. (countable) (nobility) A marchioness is a woman holding the rank of marquess in her own right. Wikiwand - on Seamless Wikipedia browsing. On steroids.Remove ads