Noun
(architecture) A vertical (or near vertical) opening (shaft) running from a courtyard to the sky, thus allowing air to circulate to high-rise apartments or offices.
Synonyms: air well, ventilation shaft, vent shaft, lightwell
(mining) A passage supplying ventilation into a mine tunnel or other underground facility.
(manufacturing) A device used for handling winding reels in the processing of web-fed materials, such as in continuous-process printing presses.
Source: en.wiktionary.org" Cotton Tail ", "Main Stem", "Harlem Airshaft", "Jack the Bear", and dozens of others date from this period. Source: Internet