(nautical) A tankship, a vessel used to transport large quantities of liquid.

(automotive, US) A tank truck.

(automotive, UK) A fuel tanker, petrol tanker, road tanker.

(aviation, usually military) An aircraft carrying a large supply of jet fuel or avgas for aerial refueling of other aircraft, plus equipment allowing the in-air transfer of fuel.

(aviation, firefighting) An aircraft built or modified to carry water and/or fire retardant for dropping on wildfires.

(rail transport) A tank car.

(military) Member of a tank crew, or of an armoured unit.

(surfing slang) A longboard.

(transitive) To transport (oil, etc.) in a tanker.

(aviation) To carry more fuel than necessary for a flight, in order to avoid having to refuel at a destination where fuel is more expensive or in short supply.