Good digging.
Also found this:
When directing Air Support, a JTAC on the ground with the unit requesting support must tell the aircraft whether or not the pilot is "cleared hot" as per official doctrine.
This tells the pilot that his or her azimuth (direction of travel) from the initial point (entrance into the engagement area) is accurate, on target, will not result in friendly fire, and is cleared to drop munitions.
-Former Paratrooper, Troop Commander, U.S. Army
https://www.quora.com/In-military-jargon-what-does-it-mean-to-come-in-hot