Side-effect is a very well-established term, though[1]: > In computer science, an operation, function or expression is said to have a side effect if it modifie

Side-effect is a very well-established term, though[1]: > In computer science, an operation, function or expression is said to have a side effect if it modifies some state variable value(s) outside its local environment, that is to say has an observable effect besides returning a value (the main effect) to the invoker of the operation. > The fact that nothing happens on the second+ invocation is, for me, the example of no unwanted side effects. I don't think you'll ever find a definition that says something about second invocations. [1] https://en.wikipedia.org/wiki/Side_effect_(computer_science) https://en.wikipedia.org/wiki/Side_effect_(computer_science)