While talking about functions, we’ve used both the terms arguments and parameters in a way that might make them seem like interchangeable words, but they’re not. Arguments are the values that we pass to a function when we call it. Parameters are the names listed in between the parentheses in the definition of the function header. So concerning our circle() example from before, it would be correct to say “circle() is a function that has two parameters called x and y.” It would also be accurate to say, “we later called the circle() function with arguments of 10 and 30.” In other words, parameters tell you what the function needs; arguments are the specific values that you give the function in any particular instance.