I think I've been unclear. When I say function definition I'm referring to this:

    function foo() {
      console.log('bar');
    }

And when referring to a function expression I'm talking about this:

    var foo = function () {
      console.log('bar');
    };

The latter needs to be terminated with a semicolon to prevent ambiguity (in some situations), while the former does not. This for example is valid JavaScript:

    function foo() {
      console.log('bar');
    }foo=5