UPSIDE DOWN Meaning of UPSIDE DOWN in English ■ adverb & adjective1》 with the upper part where the lower part should be. 2》 in or into total disorder.OriginME: orig. up so down , perh. in the sense 'up as if down'. Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004