It is called Compress.
http://www.xfutureblog.com/2007/09/27/how-to-reduce-or-compress-avi-file-size-and-upload-to-youtube/
File compression
The file extension for Microsoft Access 2007 is '.accdb'.
File Compression
MS Excel is a spreadsheet program that creates files called workbooks.
Save PPT 2007 file as .ppt format
open file in excel 2007 then press ribbon and go to Save as, you will see Excel 1997-2003 Workbook option, click on it and save file.
Open this file in Word 2007.
Microsoft Word 2007 file.
Human File 752 - 2007 was released on: USA: 19 September 2007 (48 to Life)
If you mean the type of file it is called the file extension.