A warning or alarm, especially a call to arms: "This instrument called television can teach and illuminate, cautioned Edward R. Murrow, but only to the extent that its operators choose to use it.... An era later ... Murrow's alarum remains as up to date as tonight's news” ( Harry F. Waters).
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.