By the way any fire is a back fire. I never heard that other one. I go with miss fire, but the other sounds like politically correct bull.
That was the term I was taught when I went to school for Aircraft Maintenence 15 years ago. I'm about as far from politically correct as they come. It's a way of being specific about the direction of the fire. Direction is absolutely critical when troubleshooting a problem like this. Terminology is an important tool for diagnosis, otherwise nobodys on the same page.