Game concept
Knight
The game also links it as Knights, Knight's.
From the game's encyclopedia
A Knight is a Vassal, Courtier, or Follower that fights directly in your Army.
During Battles, Knights use their Prowess Skill to fight more effectively. A high Prowess means that they will be able to inflict more damage on the enemy, and are more likely to survive or even emerge from Battle unscathed.
You gain Prestige each time one of your Knights successfully Qualifies for or wins a Grand Tournament Contest.
Knights that are given an Accolade become Acclaimed Knights.
Knights can be known by different names depending on Culture or Faith. For example, Champions, Fāris or Baghaturs.
Knights represent both the character and their retinue of troops.
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.
Knight is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "A Knight is a Vassal, Courtier, or Follower that fights directly in your Army." The game also links it as Knights and Knight's. 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.