A blit is short for bit block transfer and in general terms is the transfer of a contiguous block of data from one place in memory to another. Blitting most often refers to the copying of conceptually rectangular blocks of image data from a source surface to a destination surface.
When a blit is performed, the image being transfered may be rotated if the appropriate blit flags and values are set. The image will be copied from the source surface, rotated clockwise by the designated amount and then transferred to the destination surface.