• (n.) A writing upon the back of anything, as upon the back of a leaf or sheet already written upon on one side.
Op`is·thog'ra·phy noun [ Greek ... behind + -graphy .] A writing upon the back of anything, as upon the back of a leaf or sheet already written upon on one side. [ R.] Scudamore. 
opisthography 1. The practice of writing on both sides of an object used as a surface; such as, papyrus or stone. 2. The writing done in this fashion.