Baker’s Evangelical Dictionary of Biblical Theology is a 753 entry dictionary of Theology.
This is a dictionary taken (with permission) from the website of CARM.ORG (Matt Slick). These are definitions of theological terms. Excellent!
Buck’s Theological Dictionary still contains some interesting material, especially when it comes to Religious Sects.
A Dictionary of Catechisms from Puritan, Reformed, and several other denominations, such as Baptists, Broadus, Gadsby, Owen, etc.
This is an old dictionary of Christianity in which a lot of unused (in modern speech) terms are defined. Over 1500 entries.
Heresies of the Church Thru the Ages
Dictionary of Creeds and Confession throughout Church History, from the New Testament Times to the Twentieth Century.