[AIR- 7.] A straight passage (usually vertical) for the admission of air into a mine or tunnel.
1692. Ray, Creation, I. (1722), 77. By the sinking of an Air-Shaft, the Air hath Liberty to circulate.
1753. Chambers, Cycl. Supp., s.v., The damps … make it necessary to let down air-shafts.
1789. Mrs. Piozzi, France & It., I. 196. One of the natives … made a sort of mine, or airshaft.
