ˈair-hole
[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.
| 1766 Smollett Trav. I. xvi. 264 He said that there were air-holes at certain distances (and indeed I saw one of these). 1876 W. Boyd in Bartlett 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. |