what icon represents a link to an item rather than the item itself

I believe you are looking for a Shortcut, believing this is referring to icons on the Desktop.

It would be called a shortcut. So, you're able to create a shortcut to items, which is then a "link" to an item. For instance on your computer desktop - you have shortcuts all over the place - such as files and/or desktop icons."Shortcuts" can look like varies items like programs/files etc.  If you need more information, let me know. :)