v.1. To reset something, such as a counter or clock, to zero: The timekeeper forgot to zero out the stopwatch in between sprints. I zeroed the odometer out and measured the length of the road.
2. To reduce some quantity to zero: This final payment will zero out your balance on the loan. I called the bank and zeroed out my account.
3. To cut off the funding for something, such as a government program: The new administration is planning to zero out subsidies and benefits for illegal aliens. Our social assistance program had funding until the government zeroed it out of the budget.