It can also refer to several books, some no longer current.
The OF uses an Ordo Episcoporum which in the EF is known as the Pontificale Romanum. It has the rites for ordaining deacons, priests and Bishops, consecrating Churches, Confirmation and other rites specific to bishops.
Prior to Vatican II there were unofficial books that instructed the Bishop on how to conduct the ceremonies found in the Pontificale Romanum. While the Ceremoniale Episcoporum was the official guide to the Rites in the PR, the other guides were written by liturgical experts over the centuries to aide the Bishop and his Master of Ceremonies, as well as those who would participate in the ceremonies to know what their duties were during the ceremonies.