The Internet offers us a variety of online Latin dictionaries and glossaries that you can find helpful when studying legal historical sources. Some of them are more or less digitized versions of printed Latin dictionaries, whereas there are a few

The Lexicon Totius Latinitatis – LTL – written by Egidio Forcellini (1688–1768), an Italian priest, philologist, and lexicographer, is undoubtedly a fundamental Latin dictionary. The original text was finished in 1761 and first published in 1771. This was the most influential classical Latin dictionary until the Thesaurus Linguae Latinae came out. Search results from LTL are included in Database of Latin Dictionaries (DLD). If preferred, you can also reach for the nonsearchable PDFs of LTL at http://www.documentacatholicaomnia.eu/25_90_1688-1768-_Forcellini_Aeg.html.

A Latin Dictionary by Lewis and Short – frequently referred to as Lewis & Short, or L&S – is a Latin-English dictionary founded upon the English translation of Ethan Allen Andrews (1850) of an earlier Latin-German dictionary authored by Wilhelm Freund (Wörterbuch der Lateinischen Sprache, Leipzig, 1834–1845). Charlton T. Lewis and Charles Short revised and rewrote it. The dictionary was published by Harper and Brothers in New York in 1879 (thus it is also called Harper’s Latin Dictionary). In the same year, it was also printed by Oxford University Press. It was a basic English lexicon of classical Latin until Oxford Latin Dictionary (OLD) was released (1968–1982; 2nd ed. in 2012). The OLD covers the sources only until AD 200 though, so in terms of medieval and ecclesiastical Latin Lewis & Short still proves its usefulness, not to mention its accessibility. The Lewis & Short dictionary is included in metadictionaries (Logeion and DLD).

The Dictionnaire Illustré Latin-Français by a French philologist Félix Gaffiot (thus commonly caled Le Gaffiot) is a valuable Latin-French dictionary. It was completed and first published by Hachette in 1934 (last edition in 2000). However, it covers primarily classical Latin. The search results from Le Gaffiot are displayed in metadictionaries (Logeion and DLD).

The Thesaurus Linguae Latinae – ThLL or TLL – is a monumental dictionary and lexicon of classical Latin. It includes the vocabulary from the origins of the language until the 6th century AD. The aim of authors was to cover all remaining Latin texts from the very beginning until AD 600. Consequently, it takes into consideration early Christian writings as well. The TLL is based in Germany, being affiliated to the Bavarian Academy of Sciences (BAdW), however the International Commission for the TLL consists of the delegates representing academic institutions from all around the globe. BadW allows free access to the scanned pages of all published fascicles of the dictionary with its own simple search engine. The works on TLL, initiated by Swiss philologist Eduard Wölfflin and well-known classicist, historian, and jurist Theodor Mommsen, started in the end of the 19th century. At the moment fascicles cover the vocabulary from letter A to R (repressio), but N is not fully completed. The TLL is available also on De Gruyter’s website (https://tll.degruyter.com/), but is hidden behind the paywall.

The Glossarium ad scriptores mediae et infimae latinitatis is a Latin glossary prepared by French philologist, lawyer and historian Charles du Fresne, sieur du Cange (thus the dictionary is usually abbreviated as DuCange). It was completed in 17th century and published in three volumes in Paris in 1678. The glossary covers especially medieval Latin. At the website you can find the 19th century edition of DuCange (Niort: L. Favre, 1883–1887). Additionally, it is included in the metadictionaries (Logeion and DLD). In 1920s the International Union of Academies issued a plea to launch works in order to replace DuCange as a basic medieval Latin glossary. The works began and resulted in publishing dictionaries and glossaries of medieval Latin in several countries. Some of them are available freely online.

The Dictionary of Medieval Latin from British Sources – DMLBS – is a Latin-English dictionary edited by Richard Ashdowne, David Howlett, and Ronald Latham and originally published by Oxford University Press under the aegis of the British Academy (1975–2013). It covers the period from the 6th to the 16th centuries. It is available through metadictionaries (Logeion and DLD), however, the search scope is limited to headwords. Full version of online dictionary, available through Brepols, allows full-text searching.

The Lexicon Mediae et Infimae Latinitatis Polonorum – LMILP – is a comprehensive medieval Latin dictionary. It covers Latin used in Polish lands in 10th–16th centuries. The printed version of Lexicon has been published by the Institute of Polish Language (based in Kraków) of the Polish Academy of Sciences since 1953 (until 2023 73 issues were published and the last one ends at sum). In 2014 the digital version of LMILP was put online. The thesaurus of the digital version includes words from A to Q.

The Latinititatis Medii Aevi Lexicon Bohemorum – Lex. Bohemorum – is a dictionary of medieval Latin based upon Latin texts used in Czech lands since ca. AD 1000 to AD 1500. Until 2023 fascicles covering the vocabulary from A to M were published. The project that started in 1934 is affiliated with the Centre for Classical Studies at the Institute of Philosophy. The works are conducted in the Department of Medieval Lexicography thereof. The search results from Lex. Bohemorum are also available through DLD.

The Mittellateinische Wörterbuch – MLW –  is another example of a national dictionary of medieval Latin. The project commenced in 1939 and is still being developed. The MLW is based upon Latin texts from German-speaking countries originating in the Middle Ages, that is, from the 6th century until AD 1280. As a result, there exists a temporal link to the TLL discussed above. In terms of geography, the MLW includes also the sources originating from the Frankish Empire, the Kingdom of Italy, or even contemporary Poland or Great Britain (due to completion of DMLBS the citations from the latter are currently renounced). In 2019 the digital version of MLW was made available online free of charge at the website mentioned above. The volumes available in open access are 1 to 4, that is, from letter A to H. They are available as searchable PDFs.

Gerhard Köbler uploaded on his website an online version (HTML) of his Frühmittellateinisches Rechtswörterbuch (Lexikon frühmittelalterlicher Rechtswörter für Freunde frühmittelalterlicher Rechtsgeschichte, 1999), that is, early medieval Latin-German legal dictionary where you can find approximately 16,000 entries.

The Latinitatis italicae medii aevi lexicon is an Italian dictionary of medieval Latin prepared under the aegis of the International Union of Academies. It is based upon Latin texts from Italy originating in the Middle Ages, that is, from the end of the 5th to the beginning of the 11th centuries. The original version, published in three volumes between 1939 and 1964, was supplemented by subsequent addenda (1965–1997). All published volumes were reprinted in 2001. Since that year, the second addendum is being published. Until today 16 issues have been published. Searching through this dictionary is possible thanks to the DLD metadictionary.

Novum Glossarium Mediae Latinitatis – NGML – is a glossary prepared since 1957 by L’Institut de recherche et d’histoire des textes (IRHT), which is the part of the French National Centre for Scientific Research (CNRS). It covers medieval Latin, that is, sources from AD 800 to 1200. Until today fascicles from L to Pontentificus were published. Only volumes L-Na are available at the website mentioned above.

See also the website http://www.lexica.linguax.com where you can find a collection of Latin and Ancient Greek dictionaries. Also the Ad fontes project website provides a list of useful dictionaries.

Metadictionaries provide aggregated search results from several dictionaries. Belew you can find two most popular, namely Logeion and Database of Latin Dictionaries (DLD).

Logeion is an online Latin and Ancient Greek metadictionary hosted by the University of Chicago. It provides simultaneous lookup of entries in several digitized dictionaries. In terms of Latin dictionaries, Logeion search scope includes the following: A Latin Dictionary by Lewis and Short, Dictionary of Medieval Latin from British Sources, Glossarium ad scriptores mediae et infimae latinitatis (du Cange), Dictionnaire Illustré Latin-Français (Le Gaffiot), and Woordenboek Latijn/Nederlands (LaNe) edited by Harm Pinkster. The query scope covers, however, not only dictionaries, but other publications as well. Among them you can find selected textbooks, lexicons, and glossaries, e.g., Oxford Latin Course or Cambridge Latin Course.

Additionally, Logeion enables you to search through corpus of classical Latin texts provided by PhiloLogic4 (accessible also separately) and originally published in the Perseus Digital Library (formerly Perseus Project) founded and developed at Tufts University. You may find it useful in terms of retrieving information on frequency and collocations.

The Database of Latin Dictionaries (DLD) is provided by Brepols. It means that unfortunately the service is behind the paywall. However, many academic institutions provide access to Brepols for their members (scholars and students).

It allows to simultaneously search through several Latin dictionaries (mono-, or bilingual). It offers searching by headwords (lemmata), Latin and non-Latin word forms appearing in selected dictionaries, textual references, or in full text. Among the dictionaries included in the query you can find as follows:

• classical Latin: Forcellini’s Lexicon Totius Latinitatis, Lewis and Short’s A Latin Dictionary, Le Gaffiot;
• patristic age: Dictionnaire latin-français des auteurs chrétiens by Albert Blaise, A Glossary of Later Latin to 600 A.D. by Alexander Souter;
• medieval and early modern Latin: Lexicon latinitatis medii aeui by Albert Blaise, Du Cange, as well as national dictionaries of medieval Latin from the 20th century, that is, the Italian Latinitatis italicae medii aevi lexicon, the Hungarian Glossarium mediae et infimae Latinitatis regni Hungariae by Antonius Bartal (1901), the Spanish Lexicon Latinitatis Medii Aevi Regni Legionis (s. VIII-1230) imperfectum (2010), the British Dictionary of Medieval Latin from British Sources, and the Czech Latinitatis medii aevi Lexicon Bohemorum;
• and many other thematic and medieval dictionaries.

Abbreviations

Ad fontes website offers an online and revised version of Adriano Capelli's Lexicon abbreviaturarum (Lexicon of abbreviations). So, if you deal with an abbreviation that you can't decipher, you can easily reach Capelli.

Thanks to the École nationale des chartes we have access to online Dictionnaire des abréviations françaises, which is an expanded version of the list prepared by Maurice Prou (Manuel de paléographie latine et française).

French

The Dictionnaire du Moyen Français – DMF – is an free dictionary of Middle French (1330–1500) prepared under the auspices of CNRS. It works online, but it is possible to download the dictionary in PDF as well. According to the website in comprises more than 67 thousand entries and over 476 thousand examples. In 2023 new version of DMF was ready wich since December 2023 is available online.

National Library of France offers a digitized version of Dictionnaire de l’ancienne langue française et de tous ses dialectes du IXe au XVe siècle by Frédéric Godefroy.

You can also consult the French metadictionary – Dictionnaires d'autrefois – available thanks to the Project for American and French Research on the Treasury of the French Language (ARTFL) at the University of Chicago. It aggregates search results from several old French dictionaries, including Dictionarium latinogallicum (Latin-French dictionary) by Robert Estienne (3^rd ed., 1552), Thresor de la langue françoyse by Jean Nicot (1606), Dictionaire historique et critique by Pierre Bayle (1740), Dictionaire critique de la langue française by Jean-François Féraud, and finally Dictionnaire de l'Académie Française (1^st, 4^th, 5^th, 6^th, 8^th eds., 1694, 1762, 1798, 1835, 1923-1935).

Another worth-noticing website is Glossaire des patois de la Suisse romande affiliated with the University of Neuchâtel.

German

The Deutsches Rechtswörterbuch – DRW – is an comprehensive dictionary of historical German legal terms, which covers the period from the early Middle Ages until 19^th century. It includes not only modern German, but other Western Germanic languages and language varieties, such as: Old English, Lombardic, Old Frisian, Middle Dutch, and Middle Low German.

Althochdeutsches Wörterbuch (AWB) by Elisabeth Karg-Gasterstädt and Theodor Frings is available online thanks to the support of Sächsische Akademie der Wissenschaften zu Leipzig.

Mittelhochdeutsches Wörterbuch (MWB) is a project of Mainzer Akademie der Wissenschaften and Literatur mit der Arbeitsstelle Trier. 

Online Frühneuhochdeutsches Wörterbuch (FWB-Online) started by Oskar Reichmann covers the period of mid-14^th - mid-17^th centuries). Since 2013 it is a project run by Akademie der Wissenschaften zu Göttingen.

A worthwile portal is Wörterbuchnetz which makes it possible to search through more than 20 dictionaries, including Jacob and Wilhelm Grimms' Deutsches Wörterbuch, Mittelhochdeutsches Wörterbuch by Benecke, Müller and Zarncke, and Mittelhochdeutsches Handwörterbuch by Matthias Lexer, Mittellateinisches Wörterbuch. There are also links to several other dictionaries. 

See also a list of references on the Ad fontes project website.

Other languages

You can always check the Lexilogos website which is a hub of thousands of dictionaries of different languages. Lots of links can be found on the Gerhard Köbler's website as well.

Repertorium utriusque iuris is designed to make studying sources of Roman and canon law easier. The website contains easily searchable indices of incipits (or first words) of units of major monuments of law (from Corpus Iuris Civilis and Corpus Iuris Canonici), which can significantly facilitate the process of identifying (abbreviated) references to legal historical sources in examined materials. Similar alphabetical list (as regards Corpus Iuris Civilis) can be found here.

If you have difficulties with identifying a Latin word in the medieval or early modern manuscript, you can use ENIGMA, developed at the Centre national de la recherche scientfique. It can help to find the correct word even if a few letters are missing. They can be replaced with 'wildcards' (asterisks, dots, etc.), and ENIGMA should retrieve possible solutions of your problem.

Codicologia is a website hosted by Institut de recherche et d'histoire des textes. It contains a multilingual glossary of terms concerning description of manuscripts (Arabic, English, French, German, Italian, Spanish).

Transkribus is an AI-powered text transcription software available to download or to use through the website at https://readcoop.eu/transkribus/. Its basic jobs are automatic segmenting of the text of given manuscript into lines (Layout Analysis) and manual transcription thereof. It can be therefore useful while working on scholarly source edition or even while exploring manuscripts that constitute the primary source of your academic work.

Transkribus is a free application. After having registered on their website, you can download the programme (it runs on Windows, MacOS, and Linux) and start using it. Transkribus allows you to work with your own documents (scans or photographs of manuscripts or prints). The application works with PDF, JPEG, PNG and TIFF files.

Transkribus also gives us the option of automated recognition of text (HTR – Handwritten Text Recognition). However, this feature is not free. You can pay with with so-called Transkribus Credits that can be bought on Transkribus website. It makes it possible to have your documents recognised by the computer instead of having to decipher the handwriting by yourself. It can utilise one of the public models of recognition made available by the Transkribus community or a new self-trained model. According to the website, the computer needs around 5000 transcribed words of printed text or 15 000 words of handwritten text (that is, ca. 25–75 pages) to train its own model. The self-training is based, of course, on manually transcribed documents. Transkribus provides some professional tools for those who work on scholarly source edition as well.

For further details on the programme, its features and functionalities you can read the guides available on the Transkribus website.

You can find a list of similar projects on the Ad fontes project website.

Whitaker’s WORDS is a Latin-English translation software created by William A. Whitaker (1936–2010), an American military man, colonel of the United States Air Force, who chaired the High Order Language Working Group (HOLWG). The team, which was established in 1975 by the US Department of Defense (DoD), developed the Ada computer programming language. They reached the goal, which was to supersede hundreds of programming languages used by DoD until that time with one standardized language. After retiring, Whitaker used the Ada language to create WORDS, a Latin translation software.

The Whitaker’s WORDS contains more than 39 000 entries (lemmata). But it is more than an ordinary online dictionary. The programme offers a grammatical analysis of a typed word. It gives back information on, among others:

• part of speech type (noun, pronoun, adjective, numeral, adverb, verb, etc.);
• gender type (masculine, feminine, neuter, common);
• case type (nominative, vocative, genitive, locative, dative, ablative, accusative);
• number type (singular, plural);
• comparison type (positive, comparative, superlative);
• numeral sort type (cardinal, ordinal, distributive);
• tense type (present, perfect, imperfect, future, perfect, plusperfect, future perfect);
• number of conjugation and other characteristics of a verb (e.g., deponent, semideponent);
• voice type (active, passive);
• mood type (indicative, subjunctive, imperative, infinitive, participle);
• type of pronouns (personal, relative, reflexive, demonstrative, interrogative, indefinite).

Additionally, it provides also five basic characteristics concerning the word, that is, age, area, geography (regarding the origin or a subject), frequency, and source.

Of course, Whitaker’s WORDS is not perfect, and its thesaurus is limited mainly to classical Latin. However, it can still help students and researchers with basic vocabulary. Whitaker’s WORDS is available online, through the website. It is also possible to download the copy of the programme from your computer. Links and a user guide can be found on the website. The downloadable version is, however, designed for a DOS PC. As a result, it will probably not run on your computer.

The remedy is a programme called Legible Latin created by Thomas McCarthy. Its thesaurus is based on Whitaker’s WORDS. Legible Latin offers the same content in an up-to-date version with extra features and functionalities. In addition to analysing individual Latin words, you can also:

• paste a larger part of a text (from clipboard or file) in order to analyse it more smoothly (feedback through clicking on a selected word instead of typing each word separately) (Reading Aid);
• search for Latin translation of English words (English-Latin dictionary).

The programme allows also define the scope of the word analysis.

Legible Latin is free and can be downloaded from, for instance, here.

There exists also Whitaker’s WORDS version for Kindle, created by Thomas McCarthy (A Digital Latin Dictionary) which comes in handy when reading Latin texts in an e-book reader. It is available on Amazon.

Another simple tool that might be utilised to decode Latin words is naturally the Wiktionary. It is one of the many portals based upon the Wiki Engine that allows collaborative editing of the content through a web browser. It is a free multilingual dictionary, and one of the languages covered is Latin. Obviously, due to its character, it is not fully reliable, however it can come in handy. One of its advantages is that it provides, when visiting the page with the lemma, the full declension and conjugation of given word in the form of a table.

When exploring legal sources from the past, you may need help from the field of auxiliary sciences of history. Several online tools can here come in handy. Below you will find some of them that may be helpful.

Chronology

A variety of tools concerning chronology can be found on the Historical Auxiliary Sciences Chronology and Ad fontes websites.

Geography

General

The online digitised edition of Johann G.Th. Grässe's Orbis Latinus (1909) was prepared by Karen Green. It is a lexicon of Latin geographical names of the Middle Ages and modern times.

In addition, you can always consult the Historical Auxiliary Sciences - Historical Geography, where links redirecting to several websites are available.

France

Dictionnaire topographique de la France makes it possible to check not only contemporary, but also historical names of places.

Poland

Atlas Fontium is an online data repository developed under the aegis of the Instutite of History of the Polish  Academy of Sciences. It offers inter alia free access to the digital Historical Atlas of Poland, or Gaul/Raczyński topographic map from the turn of 18^th and 19^th centuries.

Switzerland

Toponymes.ch is a website dedicated to the research on topography and onomastics of Switzerland.

If needed, you can always consult the official Swiss geoportal where it is possible to see the historical ways in the Switzerland.

Other

Coins and measures on the Ad fontes project website.