1A word or phrase cried out to raise an alarm or call troops to arms (now chiefly historical).
2A short word or phrase used as a password; compare "watchword" (now rare).
Early 18th century.
英语词典包含464360条英英释义在线翻译词条，基本涵盖了全部常用单词的英英翻译及用法，是英语学习的有利工具。