Bible Encyclopedias
Donjon

1911 Encyclopedia Britannica

(from a Late Lat. accusative form domnionem, connected with domnus or dominos, a lord), the French term for the keep of a medieval castle, used now in distinction to "dungeon", the prison, which is only an anglicized spelling (see also Keep).

Bibliography Information
Chisholm, Hugh, General Editor. Entry for 'Donjon'. 1911 Encyclopedia Britanica. https://www.studylight.org/​encyclopedias/​eng/​bri/​d/donjon.html. 1910.