What does a steady green light gun signal indicate for an aircraft on the ground?

A steady green light gun signal indicates that an aircraft on the ground is cleared to cross or take off. This signal is used primarily by air traffic control when communicating with pilots visually, especially in situations where radio communication might not be possible.

When a pilot receives a steady green light while on the ground, it signifies that the runway or taxiway is clear, and they can safely proceed with their intended movement. This is crucial for ensuring the safe and efficient movement of aircraft, as it provides clear instructions to the pilot in a manner that is universally understood.