RPG stands for role-playing game, which is a genre of tabletop games where a group of people make believe to be other characters, often fantastical ones, with various traits and abilities who go on adventures and generally resolve skill tests through the use of various multi-phase dice.

CRPG stands for computer role-playing game, which is a term that came into prominence to differentiate it from tabletop role-playing games. Nowadays, it is generally used to refer to old school RPGs of the 90s, or modern games that take after their formulas. Usually, the biggest difference between a CRPG and an ARPG (action role-playing game) is that CRPGs are heavily dependent on the characters stats, while ARPGs favor player skill.

On the other hand, JRPG stands for Japanese role-playing game, which is a subgenre of RPGs that originated in Japan. They are characterized by their linear, story-driven gameplay, turn-based combat, and anime-inspired visuals.

Finally, ARPG stands for action role-playing game, which is a subgenre of RPGs that emphasizes real-time combat and fast-paced action. They often feature loot-based progression systems and character customization.

In summary, CRPGs are a type of RPG that is heavily dependent on the characters stats, while ARPGs favor player skill. JRPGs are a subgenre of RPGs that originated in Japan and are characterized by their linear, story-driven gameplay and turn-based combat. ARPGs are a subgenre of RPGs that emphasize real-time combat and fast-paced action.