dĭătessărōn = διὰ τεσσάρων, n. indecl.
I v. diapason.—
II A medicine made of four ingredients , Cael. Aur. Acut. 2, 18, 112; Plin. Val. 3, 22.
·noun The interval of a fourth. II. Diatessaron ·noun An electuary compounded of four medicines. I...
Webster's Dictionary of the English Language