OLEACEOUS Meaning of OLEACEOUS in English [ ˌəʊlɪ'eɪʃəs ]■ adjective Botany relating to or denoting plants of the olive family (Oleaceae).OriginC19: from mod. L. Oleaceae , based on L. olea 'olive tree', + -ous . Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004