Definition of "auxiliary verb" []

• A verb, such as have, can, or will, that accompanies the main verb in a clause and helps to make distinctions in mood, voice, aspect, and tense. (noun)

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.

• "And President Bush made official the growing use of this semimodal auxiliary verb with his answer in a news conference: “Anybody who harbors terrorists needs to fear the United States.”"