XLS is the shorthand for Microsoft Excel file extension. A file extension is the group of letters following a period in a file name, denoting what kind of file it is.
File extension.
The extension. It tells Windows what kind of a file it is. For example, a file with the ".doc" extension is a Microsoft Word Document.
The extension.
file extension
its an extension for the file name which tells about the file type. but I just have a query, why most of the extensions are three lettered
The file extension tells about the type of file, with the extension three letters. For Eg:- *.txt -- text file *.exe-- executable file
File extension.
minimum three and maximum four
It doesn't use any part of the file. It gets the extension (the part after the dot) of the file name, and looks that up in the registry to see what program should be used to open, for example, a .doc file.
File extension
A text file, usually with numbers, letters, and/or simple graphics.