MALVACEOUS Meaning of MALVACEOUS in English [ mal'veɪʃəs ]■ adjective Botany relating to or denoting plants of the mallow family (Malvaceae).OriginC17: from mod. L. Malvaceae , based on L. malva 'mallow', + -ous . Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004