What is a variable that can be accessed by any part of the program called?

A variable that can be accessed by any part of the program is referred to as a global variable. This type of variable is declared outside of any functions or methods and is available throughout the entire program, allowing different functions or methods to access and modify its value without needing to pass it as a parameter.

In contrast, local variables are defined within a specific function and can only be accessed and modified within that function. Static variables maintain their value between function calls but are still limited to the context of the function they belong to. Instance variables are associated with a particular instance of a class and can only be accessed via that instance.

Global variables are useful for storing data that needs to be shared across multiple functions, but they should be used judiciously, as excessive use can lead to code that is harder to understand and maintain due to potential unintended side effects from variable modifications.