The Jargon File (version 4.4.7, 29 Dec 2003):

blit
 /blit/, vt.

    1. [common] To copy a large array of bits from one part of a computer's
    memory to another part, particularly when the memory is being used to
    determine what is shown on a display screen. ?The storage allocator picks
    through the table and copies the good parts up into high memory, and then
    blits it all back down again.? See bitblt, BLT, dd, cat, blast, 
    snarf. More generally, to perform some operation (such as toggling) on a
    large array of bits while moving them.

    2. [historical, rare] Sometimes all-capitalized as BLIT: an early
    experimental bit-mapped terminal designed by Rob Pike at Bell Labs, later
    commercialized as the AT&T 5620. (The folk etymology from ?Bell Labs
    Intelligent Terminal? is incorrect. Its creators liked to claim that ?Blit?
    stood for the Bacon, Lettuce, and Interactive Tomato.)


The Free On-line Dictionary of Computing (30 December 2018):

blit

   /blit/ 1. To copy a large array of bits from one part of a
   computer's memory to another part, particularly when the
   memory is being used to determine what is shown on a display
   screen.  "The storage allocator picks through the table and
   copies the good parts up into high memory, and then blits it
   all back down again."  See bitblt, BLT, dd, cat,
   blast, snarf.  More generally, to perform some operation
   (such as toggling) on a large array of bits while moving them.

   2. Sometimes all-capitalised as "BLIT": an early experimental
   bit-mapped terminal designed by Rob Pike at Bell Labs,
   later commercialised as the AT&T 5620.  (The folk etymology
   from "Bell Labs Intelligent Terminal" is incorrect.  Its
   creators liked to claim that "Blit" stood for the Bacon,
   Lettuce, and Interactive Tomato).

   [Jargon File]

   (1994-11-16)