the indefinite boundary in the upper atmosphere beyond which the air is too thin for conventional aircraft to operate.
the region of the upper atmosphere above which aircraft cannot fly
the study or collection of airmail stamps, cancellations, etc.
an abnormal fear of drafts of air, gases, or airborne matter. Historical Examples He was at the same time attacked by aerophobia to a prodigious degree. Louis Pasteur Ren Vallery-Radot noun a pathological fear of draughts of air aerophobia aer·o·pho·bi·a (âr’ə-fō’bē-ə) n. An abnormal fear of air, especially drafts.
any musical wind instrument. Historical Examples He felt unwell; he felt angry; if the aerophone refused to work at all to-morrow, he would care nothing. Stella Fregelius H. Rider Haggard I think, I really think I have nearly perfected my aerophone. Stella Fregelius H. Rider Haggard Can you give me a short description of the […]