duodenum: [14] The term duodenum, for the first part of the small intestine, originated as a measure of length. It comes from the medieval Latin phrase intestinum duodēnum digitōrum ‘intestine of twelve digits’ – that is, twelve finger-breadths long, or just over 20 centimetres. Latin duodēnī meant literally ‘twelve each’; it was a derivative of duodecim ‘twelve’ (source also of English dozen). => dozen[duodenum etymology, duodenum origin, 英语词源]