liquid air

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Air in its liquid state, intensely cold and bluish, obtained by cooling and compression.

from the GNU version of the Collaborative International Dictionary of English.

• (Physics) A transparent limpid liquid, slightly blue in color, consisting of a mixture of liquefied oxygen and nitrogen. It is prepared by subjecting air to great pressure and then cooling it by its own expansion to a temperature below the boiling point of its constituents (N: -194° C; O: -183° C.).

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun air which is in a liquid state due to being pressurised or kept at a low temperature, or both, usually for storage and transport purposes.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun air in a liquid state