The Dock is the bar of icons that sits at the bottom or side of your screen. It provides easy access to some of the applications on your Mac (such as Mail, Safari, Address Book, and QuickTime Player), displays which applications are currently running, and holds windows in their minimized state. It's also the place to find the Trash (its icon looks like a waste basket). For your convenience, you can add your own applications, files, and folders to the Dock too.