<p><strong>Noun</strong></p><ul><li>The letters represented by the radio telegraphic signal (· · · – – – · · ·) used, especially by ships in distress, as an internationally recognized call for help.</li><li>Any call for help: We sent out an SOS for more typists.</li></ul><p><strong>Verb</strong></p><ul><li>(Used without object) To send an SOS.</li></ul>