1) (n) A military term. The business end of a firing range. Where all the ordnance fired, lobbed, dropped or planted does it's work. Basically every millimeter forward of the firing line. Typically contains unexploded ordnance and as such is not such a good place for a hike or picnic.
2) (n) A zone of approximately 3 feet by 5 feet in front of your boss or manager's desk.
3) (n) Anywhere in which interaction with certain people can be detrimental to your health or career.
1) The Lieutenant couldn't figure out the map again, so we ended up humping through the impact area behind the mortar range.
2) "The boss called me into the impact area today to tell me our department needs to boost throughput and reduce time to market."
3) I got off the freeway at Crenshaw and had to drive through the impact area to find a gas station.