Noun 1, the invisible gaseous substance surrounding the earth, a mixture mainly of oxygen and nitrogen. air regarded as necessary for breathing; the free or unconfined space above the surface of the earth; referring to the use of aircraft; the earth's atmosphere as a medium for transmitting radio waves; one of the four elements in ancient and medieval philosophy and in astrology (considered essential to the nature of the signs of Gemini, Aquarius, and Libra); a breeze or light wind 2, an impression of a quality or manner given by someone or something an annoyingly affected and condescending manner 3, a tune or short melodious song 4, a jump off the ground on a snowboard or skateboard verb; 1. express (an opinion or grievance) publicly broadcast (a programme) on radio or television; parade or show (something) ostentatiously 2. expose (a room) to the open air in order to ventilate it warm (washed laundry) to remove dampness; go out in the fresh air