If you pay attention to the dock in Mac, you will notice that it is split into two sections – the left, which contains the app launchers, and the right that contains the trash bin and the stacks. By default, when you minimize an app window, it will minimize itself to the right section of the dock, instead of its own app icon on the left. If you minimize several windows at the same time, this will quickly clutter up the dock and make it very messy.
There is a way to reduce the dock clutter. Open the System Preferences and go to the Dock section. Check the box beside “Minimize windows into application icon”.
That’s it. Now, when you minimize the window, it will minimize to its own app icon, rather than taking a space in the right side of the dock. To relaunch your application, you just have to click the app icon, or right click on it to select the window (if you have multiple windows of the same app minimized).