ēvŏlūtĭo, ōnis, f. [evolvo, I. B. 1.],
an unrolling or opening of a book; hence, a reading : quid poëtarum evolutio voluptatis affert? Cic. Fin. 1, 7, 25.
ēvolūtiō ōnis, f ex + 3 VOL-, an unrolling : poētarum, reading . ...
An Elementary Latin Dictionary