The term either or both “app icon(s)” or “app cover(s)”—and, most relevantly, whenever used on my site here (plus according to any numberless amount of circumstances where I’ve since seen either/or terms used)— refers to a very similar meaning, if not the same thing… in some cases (which would depend how, where, or in what context said term is being used), meaning:1) an app icon— in literally every context— refers to the little square(s) which appear and may wiggle about on the Home Screen of your device(s)’ where you see your various apps displayed. An app icon simply refers to not the app itself— or anything involving any app’s purpose— but refers to what the app’s “button” looks like on your device so that you can find the app and click on it. Usually— if not, always (or almost always)— your app icons will include the name of the app around it (usually in typed text right below the app). For example, when you access your phone and go to it’s Home Page (with all it’s contents and features; after entering your password and/or which would be after passing by the Lock Screen)… you will have a visual of all your apps. You may have just a couple. You may have many. Nowadays, just about all phones and/or it’s associated devices (like, an iPad/tablet, for example) will automatically come preinstalled with some apps for your convenience or, sometimes, simply due to the popularity of certain apps… yes, some phones/devices will include such apps already installed. Needless to say, these little “buttons” (for lack of a better word to otherwise describe the word “icon”— as “icon” is the correct term):