Verso

·noun The reverse, or left-hand, page of a book or a folded sheet of paper;

— opposed to recto.

verso
verso (vorso), āvi, ātum, 1 (inf. vorsarier, Plaut. Poen. 1, 2, 53), v. freq. a. [verto], to turn,...

A New Latin Dictionary by Charlton T. Lewis Ph.D. and Charles Short, LL. D.
verso
versō or vorsō āvī, ātus, āre, freq.verto, to turn often, keep turning, handle, whirl about, turn ...

An Elementary Latin Dictionary