Encyclopaedia Judaica. 2nd ed . 22 volumes (2007)
The second edition of this great reference work updates both articles and bibliographies and includes new topics.
A website which contains the complete contents of the 12-volume Jewish Encyclopedia, which was originally published between 1901-1906. The Jewish Encyclopedia, which recently became part of the public domain, contains over 15,000 articles and illustrations.
Jewish Women : a comprehensive historical encyclopedia
A resource for anyone interested in Jewish women anywhere, at any time.
This extensive lexicon, compiled by Joseph Galron-Goldschlager, includes a description and bibliography for nearly every important author of Hebrew literature. (In Hebrew)
YIVO Encyclopedia of Jews in Eastern Europe
This encyclopedia provides the most complete picture of the history and culture of Jews in Eastern Europe from the beginnings of their settlement in the region to the present. This Web site makes accurate, reliable, scholarly information about East European Jewish life accessible to everyone.
Milon Even Shoshan
Israel : ha-Milon he-hadash, 2003. 6v.
PJ4830 .E93 2003
The dictionary attempts to be, as far as possible, a complete compendium of everyday spoken and written Hebrew, and, being a general dictionary, it intentionally does not include a lot of scientific and technological terminology. Another characteristic of the dictionary is that it is constructed in a manner that describes the vocabulary of contemporary Hebrew in combination with all its historical periods.
If you are searching for Hebrew or Yiddish language material, you will need to know how to romanize in order to search library catalogs and WorldCat.
North American libraries generally use the Library of Congress system of romanization: http://www.loc.gov/catdir/cpso/romanization/hebrew.pdf
Be aware that there are several other systems of romanization in use.