Dictionary of Liturgical Latin by Fr Wilfrid Diamon

Liturgical Latin, obviously enough to anyone who has even a smattering of the language, is not the Latin of the classical writers. Liturgical Latin, for the most part, is the common Latin of the people with a vocabulary suited to its use. Some Latin words were "christianized" - ie., given meanings not found in dictionaries of classical Latin. Variant spellings are also quite common in the ecclesiastical books. Here are over 11,000 words - gathered from Scriptures (including the New Latin Psalter), the Breviary, the Missal, and other church books - a good percentage of which are not to be found at all in classical dictionaries, and almost all of which have a peculiar meaning in ecclesiastical use.