On a Mac computer, what is the equivalent of the Windows "Start" button?

On a Mac, instead of the start button in the bottom left-hand corner, there is an apple button in the upper left-hand corner. On the keyboard, instead of a Windows key there is Command key.

The Apple menu that is accessed by the apple button or the command key is similar to the start menu on Windows. This menu is used to access many functions, such as Software Update, System Preferences, Sleep, Log Out and Shut Down. One thing very different about the Mac setup is that the minimize, maximize and exit buttons are on the left corner of a program instead of the right corner.