The full form of GIF is Graphics Interchange Format.

Stands for “Graphics Interchange Format.” GIF is an image file format commonly used for images on the web and sprites in software programs. Unlike the JPEG image format, GIFs uses lossless compression that does not degrade the quality of the image. However, GIFs store image data using indexed color, meaning a standard GIF image can include a maximum of 256 colors.

'GIF' (tm) is CompuServe's standard for defining generalized  color raster   images.    This   'Graphics  Interchange  Format'  (tm)  allows
   high-quality, high-resolution graphics to be displayed on a  variety  of
   graphics  hardware  and is intended as an exchange and display mechanism
   for graphics images.  The image format described  in  this  document  is
   designed  to  support  current  and  future image technology and will in
   addition serve as a basis for future CompuServe graphics products.
        The main focus  of  this  document  is  to  provide  the  technical
   information  necessary  for  a  programmer to implement GIF encoders and
   decoders.  As such, some assumptions are made as to terminology relavent
   to graphics and programming in general.
        The first section of this document describes the  GIF  data  format
   and its components and applies to all GIF decoders, either as standalone
   programs or as part of  a  communications  package.   Appendix  B  is  a
   section  relavent to decoders that are part of a communications software
   package and describes the protocol requirements for entering and exiting
   GIF mode, and responding to host interrogations.  A glossary in Appendix
   A defines some of the terminology used in  this  document.   Appendix  C
   gives  a  detailed  explanation  of  how  the  graphics  image itself is
   packaged as a series of data bytes.