Game concept
Military Order
The game also links it as Military Orders, Military Order's, Military Orders', Military Order Patronage.
From the game's encyclopedia
A Military Order is a type of Holy Order populated by warriors sworn to defend and expand the lands of their Faith.
Same-Faith Rulers may hire the Order if they are at War with a hostile or evil Faith, at the cost of Piety. Once this War ends, the Order no longer fights for that Ruler.
A Holy Order may have a Military Order Patron, who does not need to pay to engage their services.
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.
Military Order is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "A Military Order is a type of Holy Order populated by warriors sworn to defend and expand the lands of their Faith." The game also links it as Military Orders, Military Order's, Military Orders' and Military Order Patronage. Patch 1.20.1.2, from game/common/game_concepts/pam_game_concepts.txt and game/localization/english/game_concepts_l_english.yml.
Source: game/common/game_concepts/pam_game_concepts.txt, game/localization/english/game_concepts_l_english.yml and the English localisation, Crusader Kings III 1.20.1.2.