<p><strong>Noun:</strong></p><ul><li>A system, especially a government postal system, of sending mail by airplane.</li><li>A letter, package, etc., sent by this system.</li><li>A stamp authorizing delivery of mail by this system.</li></ul><p><strong>Adjective:</strong></p><ul><li>Of or relating to airmail.</li></ul><p><strong>Adverb:</strong></p><ul><li>By airmail: Send all overseas letters airmail.</li></ul><p><strong>Verb (used with object):</strong></p><ul><li>To send via airmail: I airmailed the package yesterday.</li></ul>