Control key
Macintoshes also have a Control key, but it has different functionality. The original Apple mouse design reduced complexity by only offering one button. As the interface developed, contextual menus were offered to access extra options. Another button was needed to access these. On Unix and Windows, the user had other mouse buttons to use. On Classic Mac OS and macOS, the Control key is used to invoke a "right-click". Apple calls this a "secondary click" as left-handers can choose which side this button is on.