[AIR- 7.]
1. A hole or passage to admit air; spec. A hole that forms in the ice in rapid rivers over the main current, for which it is a breathing-place.
c. 1450. in Wright’s Voc., 237. Hoc columber, a are-hole.
1766. Smollett, Trav., I. xvi. (Jod.). There were airholes at certain distances.
1876. W. Boyd, in Bartlett’s Dict. Amer., The ice on the St. Lawrence at Montreal never becomes stationary for the winter until one or more air-holes have formed in it in that neighbourhood.
1883. C. Holder, in Harper’s Mag., Jan., 190/1. The air-holes open and shut at the will of the insect.
2. ‘The cavities in a metal casting—produced by the escape of air through the liquid metal.’ Ure, Dict. Arts.
1813. Southey, Nelson, vii. 249. [The guns] were probably originally faulty, for the fragments were full of little air-holes.
