N.I.C.E.
The "National Institute for Co-ordinated Experiments;" it is a new scientific institution that appears to be part of a progressive scientific movement, but is in reality a front for a Satanic organization that intends to take over and enslave the human race through scientific control.
Edgestow
A fictional small town in England, home to the University of Edgestow (comprising the College of Bracton and others) and, later, the N.I.C.E.
Bracton
A fictional college in the small English town of Edgestow
Perelandra
the second planet from the sun, known as Venus to Earthlings; the setting of the second novel, Perelandra, and the planet to which Ransom returns at the end of That Hideous Strength.
Thulcandra
Another name for Earth, known as the "Silent Planet" on account of its being cut off from the rest of the Solar System because of its fall to sin. It is also the planet on which the action of the novel is entirely set.
Malacandra
Another name for the planet Mars, the planet to which Ransom is taken in Out of the Silent Planet. Also used to refer to the Oyarsa of Malacandra.
Oyarsa
(pl. Oyéresu) an archangel-like being with great power ruling over a planet in the Field of Arbol
Field of Arbol
Another name for the Solar System (Arbol = Sun)
The Black Archon
Another name for Satan/Lucifer, who is a fallen Oyarsa ruling over the planet Thulcandra (Earth).
eldila
spiritual beings who live primarily in the Field of Arbor (space of the Solar System) and watch over the affairs of rational beings; essentially equivalent to angels.
Old Solar
otherwise known as Hressa-Hlab and Hlab-Eribole-Cordi; it is the common language across all inhabited planets (and on Earth before the Fall).
The Old One
the Malacandran/Perelandran name for God
Maleldil the Younger
the Malacandran/Perelandran name for Jesus, the Son of God and Savior of humanity
bent
"Bent" is the closest Malacandran/Perelandran equivalent to an expression of sin and evil. Earth is "bent," in their view, being the "Silent Planet" under the rule of a corrupt Oyarsa, the "black archon."
Northumberland
The name of the other main college in the fictional University of Edgestow.