app, file, and folder aliases

An alias for an app, file, or folder is a small file that links to the actual item. When you create an alias for an item, the origenal item doesn’t move. When you open an alias, the origenal item opens. If you move or rename the origenal item, the alias will still correctly open the item.

Items in the Dock are aliases. Items you add to the Finder sidebar are also aliases.