Definition - What does Zero Tape mean?
A zero tape is a tape that is printed out of a voting machine before an election begins, which should show that there are zero votes that have been counted. In the context of the law, zero tapes are an important measure to make sure that voter fraud is not taking place.
Justipedia explains Zero Tape
There could be a problem at a voting station if a voting machine does not have a zero tape before an election beings. For example, if officials tested the voting machine and the machine said that there had already been 10,000 votes for a specific candidate before the polls even began, this could be problematic. It does not necessarily mean that voter fraud is taking place. It could be a malfunction of the machine; however, zero tapes are still an important counter-fraud and voting accuracy measure.