No matter how good the glossary is in the back of your Latin textbook, it can only take you so far. Everybody needs a Latin dictionary, and if your particular interest is Church Latin, you need a specialized Latin dictionary. Here are some suggestions:
- A Dictionary of Ecclesiastical Latin by Fr. Leo F. Stelten usefully has words from all eras of Latin used by the Catholic Church, up to the present day. Nota bene: This would not take the place of a standard (including Classical Latin terms), full dictionary, like the Cassell’s, but is an important one to have besides! Try and find used at your favorite online bookseller.
- A Dictionary of the Psalter by Fr. Matthew Britt is a reprint from the early 1900’s defining words from the Divine Office, especially as found in the psalms. This will be especially useful for you in reading the hymns of the Breviary, etc. Buy from the CMAA’s shop or find it scanned online here.
- An superb online resource for helping with translations, identifying word forms’ possible conjugations/declensions as you type, is Latdict: Latin Dictionary and Grammar Resources. I love it! I hope they keep that site up forever. Besides identifying word forms and defining them, the site also provides the Latin words’ stats: ages and areas each term was used in, and its relative frequency in texts. Interesting AND helpful!
- The Online Latin Dictionary (I think run by Italians?) does what no paper dictionary can do. It takes your word form and it will present you with all the grammatical forms of a conjugation/declension, etc., that it could possibly be, and what different words it could be attached to. That’s insanely useful, since in Latin many different words (especially tricky verbs) will have some of the same forms for completely different terms.
- The (scanned and uploaded text) Dictionary of Liturgical Latin from 1961 is a very basic, to-the-point reference, compiled by Fr. Wilfrid J. Diamond.
- Liturgical Dictionary by Alexius Hoffman, O.S.B. (1928) (another scanned and uploaded text) From the Preface: “The books to which this volume will serve as a companion are the Vulgate (the Latin Bible), the Roman Missal, Breviary, Martyrology, Ritual, Pontifical and Ceremonial of Bishops; also several compendiums of Sacred Liturgy.”
I hope that this post gives you some ideas as to which dictionary options are most helpful for your needs. Latin dictionaries are an essential tool–get a good one!