DUODECIMO Meaning of DUODECIMO in English [ ˌdju:ə(ʊ)'dɛsɪməʊ ]■ noun ( plural ~s ) a size of book in which each leaf is one twelfth of the size of the printing sheet.OriginC17: from L. (in) ~ 'in a twelfth'. Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004