Sibylline Books pl n (Classical Myth & Legend) (in ancient Rome) a collection of prophetic sayings, supposedly bought from the Cumaean sibyl, bearing upon Roman policy and religion Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014