When you copy an item to the clipboard the item remains in the document as well. When you cut an item to the clipboard the item is removed from the document and only exists in the clipboard.
The practical distinction is: copying items to the clipboard is safer than cutting them to the clipboard. If you cut an item to the clipboard and make a mistake that erases the contents of the clipboard, the imformation in the clipboard can't be recovered. However, if you copy an item to the clipboard and make a mistake that erases the item from the clipboard, the item still exists in the document and can be copied again. Copying an item is less efficient than cutting an item if you have to go back and remove the item form the original location, but it can be a safer alternative.
Copyright 1996 by the Curators of the University of Missouri