Uncaught ReferenceError: plus is not defined

This error message usually occurs when you try to use a variable or function that has not been declared or defined in your code. In this case, the error is specifically stating that the variable "plus" is not defined.

To resolve this error, you need to make sure that the variable "plus" is declared and defined before using it in your code. Here's an example of how you can define and use the "plus" variable in JavaScript:

// Declare and define the plus function
function plus(a, b) {
  return a + b;
}

// Call the plus function
console.log(plus(2, 3)); // Output: 5

Make sure that the variable or function you are trying to use is properly declared and defined in your code before using it.