What does it mean in engineering/construction? In software, it means all the crappy code you wrote in hurry to meet a deadline, which you always intended to go back and fix but never did, and now it's biting you in the arse.
Its either items of work that doesn't meet spec or assurance documentation that is not complete and you need to get sorted out before close-out (and final payment).
I think technical debt means something completely different in my work (civil engineering/construction).