A dirt dive is the ground rehearsal of a planned skydive. Jumpers walk through the exit, the formations and the breakoff on the ground, in sequence, before boarding.
Why it is taken seriously
Freefall offers no opportunity to discuss a plan. Everything has to be understood before exit, so groups rehearse until the sequence is automatic — often using a creeper, a low wheeled board that lets jumpers move in belly position on the floor.
Watching a group dirt dive on the grass is one of the more recognisable sights at a drop zone.
These pages explain what things are so the language makes sense. They are not instruction and cannot substitute for it — skydiving is taught in person by rated instructors at a drop zone, and anything involving equipment handling or emergency procedures belongs there rather than on a web page.