However, we’re going to focus on the 4th, which can be added to a chord in two ways. If you just shove it onto the triad, it’s referred to as an ‘add11’. You can also use it to replace the (Major or Minor) 3rd from the original triad, in which case we refer to it as a ‘suspended 4th’. It’s also quite a tricky note: although not strictly dissonant, it has a restless sound and often strives to resolve to the Major 3rd. This creates the old Pinball Wizard, Hold Your Head Up, Brass In Pocket cliché. But that’s been overdone, so let’s not go there!