Source : WordNet®

BLT
     n : sandwich filled with slices of bacon and tomato with lettuce
         [syn: {bacon-lettuce-tomato sandwich}]

Source : Free On-Line Dictionary of Computing

BLT
     
        1. /B-L-T/, /bl*t/ or (rarely) /belt/ Synonym for {blit}.
        This is the original form of {blit} and the ancestor of
        {bitblt}.  It refers to any large bit-field copy or move
        operation (one resource-intensive memory-shuffling operation
        done on pre-paged versions of {ITS}, {WAITS} and {TOPS-10} was
        sardonically referred to as "The Big BLT").  The jargon usage
        has outlasted the {PDP-10} BLock Transfer instruction from
        which {BLT} derives; nowadays, the {assembly language}
        {mnemonic} {BLT} almost always means "Branch if Less Than
        zero".
     
        2. bacon, lettuce and tomato (sandwich).
     
        [{Jargon File}]