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 languagemnemonicBLT almost always means "Branch if Less Than zero". 2. bacon, lettuce and tomato (sandwich). [Jargon File]