an aircraft is taxiing when it is moving along the ground under its own power

Taxiing is the process by which an airplane moves on the ground, typically for takeoff or parking positions. Not every aircraft can steer its wheels, and powerful jet engines can damage nearby structures, so taxiing is often performed by powerful ground cars.

Taxiing refers to an aircraft moving under its own power on the ground, usually on wheels, but also includes aircraft with skis or floats (for water-based travel).