A cartouche was a motif featured in the Rammahgon, one of the sacred Jedi texts. It was shaped like a cylinder and contained Protobesh text that read "COURAGE".
On page 53 of Star Wars: The Rise of Skywalker: The Visual Dictionary, a note about the Rammahgon refers to a "Protobesh cartouche containing the name 'Exegol'", but the letters inside the cartouche actually spell out the word "COURAGE".
In real-life, a cartouche is an illustration or piece of stone resembling an unrolled scroll, often with writing on it and used as a decorative element.
- Star Wars: The Rise of Skywalker: The Visual Dictionary