ĕpīstŏlĭcus — Lewis & Short
ĕpīstŏlĭcus, a, um, adj., = e)pistoliko/s,
I pertaining to or consisting of letters, epistolic: Epistolicae Quaestiones, the title of a work of Cato, Gell. praef. § 9; 7, 10, 2;
and of Varro,id. 14, 7, 4; 14, 8, 2.