bitblt /bit'blit/ [{BLT}] 1. Any of a family of closely related algorithms for moving and copying rectangles of bits between main and display memory on a {bit-mapped} device, or between two areas of either main or display memory (the requirement to do the {Right Thing} in the case of overlapping source and destination rectangles is what makes BitBlt tricky). 2. {blit}, {BLT}. [{Jargon File}]