From Longman Business Dictionary
GIFGIF /gɪf/ noun [uncountableU] trademarkCOMPUTING (Graphic Interchange Format) a computer file containing images with up to 256 colours. GIF files are used especially on web sites, but they are not considered suitable for professional printingA GIF file employs lossless data compression so that the file size of an image may be reduced without degrading the visual quality.