Individual Dictionaries
Easton's
Bible Dictionary Although this reference work is valuable
in many respect, it presents a denominational view regarding
salvation.
The Catholic Encyclopedia, valuable resource in understanding
Catholic doctrine, Catholic Church history, and documenting
changes in Catholic doctrine. 
Condensed
Biblical Cyclopedia, by StudyLight.org.
JewishEncyclopedia.com,
this website contains the complete contents of the 12-volume
Jewish Encyclopedia, which was originally published between
1901-1906.
Religions
Dictionaries on yourDictionary.com.
Resources include Baker's Evangelical Dictionary of Biblical
Theology, The Catholic Encyclopedia, Hitchcock's Bible
Name Glossary, Strong's Exhaustive Concordance of the
Bible, Vine's Expository Dictionary of New Testament Words,
and many more.
Vine's Expository Dictionary of New Testament Words.
This is one of the best Bible Dictionaries.
