Game concept
Prince-Elector
The game also links it as Prince-Electors.
From the game's encyclopedia
Prince-Electors are the 7 Electors who select a Title Heir along with the Emperor under the Princely Elective Succession Law used by Holy Roman Empire.
Holders of 7 preferred Titles are prioritized as Prince-Electors. These Titles are selected when the Empire is created.
If a Prince-Elector Title is destroyed, not held by a De Jure Imperial Vassal, held by another Prince-Elector, or the Holder's Religion differs from the Emperor's, another De Jure Title held by a direct Imperial Vassal or Independent Ruler will be selected based on these criteria:
• Rulers of Emperor's Faith and Culture are favored
• Theocratic and Feudal Rulers are favored
Preferred Titles are listed in the Election view
The game's text for patch 1.20.1.2. Words in blue are entries of the encyclopedia: hover one to read it, as in the game.
Prince-Elector is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "Prince-Electors are the 7 Electors who select a Title Heir along with the Emperor under the Princely Elective Succession Law used by Holy Roman Empire." It is part of Elector. The game also links it as Prince-Electors. Patch 1.20.1.2, from game/common/game_concepts/00_game_concepts.txt and game/localization/english/game_concepts_l_english.yml.
Source: game/common/game_concepts/00_game_concepts.txt, game/localization/english/game_concepts_l_english.yml and the English localisation, Crusader Kings III 1.20.1.2.