Widescreen is a 16X9 aspect ratio, the same as most TVs today, computer screens, etc. So if you watch something in widescreen, it fills up the screen. It is called widescreen, because the aspect ratio of video and movies used to be 4X3 (the older square TVs). Anamorphic widescreen is typically 2.35:1 aspect ratio. This is where you get the black bars above and bellow the screen. That size is the standard size for cinema screens, and this is the size movies are filmed with.
forward slash. The forward slash (or simply slash) character (/) is the divide symbol in programming and on calculator keyboards. For example, 10 / 7 means 10 divided by 7. The slash is also often used in command line syntax to indicate a switch. For example, in the DOS/Windows Xcopy statement xcopy *.* d: /s, the /s is a switch that tells the program to copy all subfolders.
Alternatively referred to as a backward slash and reverse solidus, the backslash is a character ( \ ) first introduced by Bob Bemer in 1960. Note: Although slash is most often used to describe the forward slash, it could be used to describe either a forward slash or backslash.