ROSACEOUS Meaning of ROSACEOUS in English [ rəʊ'zeɪʃəs ]■ adjective Botany relating to or denoting plants of the rose family (Rosaceae).OriginC18: from mod. L. Rosaceae (based on L. rosa 'rose') + -ous . Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004