However, the Gnostic Mass ritual text Liber XV also has for its full title O.T.O. Ecclesiae Gnosticae Catholicae Canon Missae. In this case, the Latin phrase canon missae clearly carries its original meaning, and not the acquired sense that is common in Roman Catholic usage. Liber XV provides the rule or standard for an entire Mass, and not a "canon" component within one.
It is interesting to note, however, that other Thelemic Gnostic verbiage has already begun to undergo a degeneration comparable to the one by which "canon" acquired its more specific meaning in Roman Catholicism. Gnostic Mass participants can sometimes be heard or observed referring to "Liber Fifteen" as a thing done, an event or activity, which is properly speaking The Gnostic Mass, rather than as a document as the word Liber ("book") plainly indicates. Just so, Roman Catholic liturgists often refer to the "canon" as a performative component of their mass, rather than simply a section within their missal.