What does a flashing green light signal indicate to an aircraft on the ground?

A flashing green light signal indicates that the pilot has clearance to taxi. This signal is part of the visual communication system used at airports to provide directions to pilots on the ground. When a flashing green light is observed, it is a clear indication that the aircraft is permitted to move along the taxiways—essentially signaling that conditions are favorable for taxiing.

This is particularly important in maintaining safety and efficiency on the ground, allowing pilots to ensure they are moving at the appropriate times without additional clearance or confusion. Understanding light signals such as this is crucial for pilots to navigate airport environments safely. In contrast, other answers pertain to different types of signals that would indicate various actions not related to the clearance to taxi.