What s the difference between story mode and gta online?

The verified evidence discusses the development and release history of Grand Theft Auto V, including its release across multiple platforms and the collaboration between Rockstar North and other international studios. However, it does not provide details about the game's modes, such as Story Mode or GTA Online. To accurately answer the question about their differences, additional sources would be required that specifically describe these modes, their features, and how they function within the game. Without such information, I cannot provide a comparison based on the given evidence.