In Windows, starting with Windows 95 and ending with Windows 7, the Start menu is a launching pad for all the applications and control panels in the computer. Application installation programs place an icon in the Programs or All apps section of the Start menu. Depending on the version of Windows, users can rearrange some parts of the Start menu. Start is also used to turn the machine off. The default location of the Start menu button is the left bottom left side of the taskbar.
From Start Menu to Start Screen
Windows 8 changed the Start menu dramatically, turning it into a tablet-style interface with tiles, which was carried over to Windows 10. The Windows keyboard key opens the Start menu or the Start screen. See Win Start menu
and Win10 Start menu