A TIFF file, or TIF file, stands for Tagged Image File Format. TIF files are a common file format for images, especially those used on graphic design. The file extension for a TIFF file is either .tiff or .tif.
TIFF files can be saved without compression, or they can be compressed to lower file size, similar to JPG files. TIFF files are commonly used in print design and desktop publishing because they can store large, high quality images such as photos. Often, printers will prefer or require TIFF files over JPG images or other formats.
TIFF files are raster images and platform independent, meaning they will work on various operating systems such as Mac and Windows. The format was developed in 1986 by Aldus Corporation and scanner manufacturers.
Sources: Adobe.com