Anglo-Norman Dictionary
This is the online version of the Anglo-Norman Dictionary; it is a substantially revised and greatly expanded edition. Users can browse by headwords and can search with specific forms, citations, and translations.
Latin Dictionary and Grammar Aid (University of Notre Dame)
This site enables translation of terms (from Latin to English and English to Latin) and offers a wordlist intended to aid in the reading of Medieval Latin.
Medieval German: Mediaevum
This site has a number of links to various Medieval German dictionaries: Mittelhochdeutche; Mittelniederdeutsches, Althochdeutsch, Gotisch, Neuhochdeutch, and more.
Middle English Dictionary
The online version of the 2001 printed edition of the MED, this database offers a comprehensive analysis of lexicon and usage for the period 1100-1500.