duodenum (n.) Look up duodenum at Dictionary.com
late 14c., from Medieval Latin duodenum digitorium "space of twelve digits," from Latin duodeni "twelve each." Coined by Gerard of Cremona (d.1187), who translated "Canon Avicennae," a loan-translation of Greek dodekadaktylon, literally "twelve fingers long," the intestine part so called by Greek physician Herophilus (c.353-280 B.C.E.) for its length, about equal to the breadth of twelve fingers.