Definition of "stimulus" []

• Something causing or regarded as causing a response. (noun)
• An agent, action, or condition that elicits or accelerates a physiological or psychological activity or response. (noun)
• Something that incites or rouses to action; an incentive: "Works which were in themselves poor have often proved a stimulus to the imagination” ( W.H. Auden). (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.

• "* -- Here we place any reaction which is a repetition of any previous stimulus from amongst the ten next preceding, at the same time placing * repetition of preceding stimulus* under a separate heading."
• "If the quantity of sensorial power remains the same, and the quantity of stimulus be lessened, a weakness of the fibrous contractions ensues, which may be denominated _debility from defect of stimulus_."
• "President Obama avoided the term "stimulus" last night in his speech before Congress."