Skeuomorphism is a design approach where something digital is made to look or behave like a familiar physical object. A notes app might look like a paper notebook, or a button might seem raised as if it could be pressed.
That resemblance can help people guess what a control is for, especially when the app is new to them. It is like drawing a trash can to show where deleted items go.
Too much imitation can make a screen feel cluttered or confusing. The familiar detail should help explain how something works, not just imitate an object for decoration.