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.
duodenum du·o·de·num (dōō'ə-dē'nəm, dyōō'-, dōō-ŏd'n-əm, dyōō-)
n. pl. du·o·de·nums or du·o·de·na (dōō'ə-dē'nə, dyōō'-, dōō-ŏd'n-ə, dyōō-)
The beginning portion of the small intestine, starting at the lower end of the stomach and extending to the jejunum.