To move backwards from a certain position; SYN. back off, back down.
When you are explaining something, and you repeat something that you already said, you back up.
The ability of an expert system to try alternative solutions in an attempt to find an answer. The various alternatives can be viewed as branches on a tree: in backtracking, the program follows one branch and, if it reaches the end without finding what it seeks, backs up and tries another branch.
To make a copy of (a computer file) esp. for storage in another place as a security cop