An aerodrome (Commonwealth English) or airdrome (American English) is a location from which aircraft flight operations take place, regardless of whether they involve air cargo, passengers, or neither, and regardless of whether it is for public or private use. Aerodromes include small general aviation airfields, large commercial airports, and military air bases.
The term airport may imply a certain stature (having satisfied certain certification criteria or regulatory requirements) that not all aerodromes may have achieved. That means that all airports are aerodromes, but not all aerodromes are airports. Usage of the term "aerodrome" remains more common in Ireland and Commonwealth nations, and is conversely almost unknown in American English, where the term "airport" is applied almost exclusively.
A water aerodrome is an area of open water used regularly by seaplanes, floatplanes or amphibious aircraft for landing and taking off.
In formal terminology, as defined by the International Civil Aviation Organization (ICAO), an aerodrome is "a defined area on land or water (including any buildings, installations, and equipment) intended to be used either wholly or in part for the arrival, departure, and surface movement of aircraft."
The word aerodrome derives from Ancient Greek ἀήρ (aḗr), air, and δρόμος (drómos), road or course, literally meaning air course. An ancient linguistic parallel is hippodrome (a stadium for horse racing and chariot racing), derived from ἵππος (híppos), horse, and δρόμος (drómos), course. A modern linguistic parallel is velodrome, an arena for velocipedes. Αεροδρόμιο is the word for airport in Modern Greek, which transliterates as aerodromio.
In British military usage, the Royal Flying Corps in the First World War, and the Royal Air Force in the First and Second World Wars, used the term—it had the advantage that their French allies, on whose soil they were often based, and with whom they co-operated, used the cognate term aérodrome.