the minimum air gap distance to the ground of the energized conductor

air to air heat recovery unit

air to air missile launching envelope

air to air system

balanced-to-ground

bypass to ground

Capacitor to Ground

clearance to ground

cloud to ground discharge

Cloud to ground lightning

connected to ground

From underground to ground

Ground air pressure field

isolated neutral-point to ground

Single-fault to Ground

Single-phase to Ground Fault

air to surface area ratio

air to water

air to water heat exchanger

air to water ratio