Search Result for "stimulus": 
Wordnet 3.0

NOUN (1)

1. any stimulating information or event; acts to arouse action;
[syn: stimulation, stimulus, stimulant, input]

The Collaborative International Dictionary of English v.0.48:

Stimulus \Stim"u*lus\, n.; pl. Stimuli. [L., for stigmulus, akin to L. instigare to stimulate. See Instigare, Stick, v. t.] 1. A goad; hence, something that rouses the mind or spirits; an incentive; as, the hope of gain is a powerful stimulus to labor and action. [1913 Webster] 2. That which excites or produces a temporary increase of vital action, either in the whole organism or in any of its parts; especially (Physiol.), any substance or agent capable of evoking the activity of a nerve or irritable muscle, or capable of producing an impression upon a sensory organ or more particularly upon its specific end organ. [1913 Webster] Note: Of the stimuli applied to the sensory apparatus, physiologists distinguish two kinds: (a) Homologous stimuli, which act only upon the end organ, and for whose action the sense organs are especially adapted, as the rods and cones of the retina for the vibrations of the either. (b) Heterologous stimuli, which are mechanical, chemical, electrical, etc., and act upon the nervous elements of the sensory apparatus along their entire course, producing, for example, the flash of light beheld when the eye is struck. --Landois & Stirling. [1913 Webster]
WordNet (r) 3.0 (2006):

stimulus n 1: any stimulating information or event; acts to arouse action [syn: stimulation, stimulus, stimulant, input]
Moby Thesaurus II by Grady Ward, 1.0:

88 Moby Thesaurus words for "stimulus": activator, aggravation, agitation, animation, animator, antecedents, arousal, arouser, arousing, bait, base, basis, boost, bribe, call, carrot, catalyst, causation, cause, cause and effect, determinant, determinative, electrification, element, encouragement, energizer, etiology, exacerbation, exasperation, excitation, excitement, exhilaration, factor, fillip, fomentation, galvanization, goad, ground, grounds, human dynamo, impetus, impulse, incentive, incitation, incitement, inducement, inflammation, infuriation, instigation, interest, invitation, irritation, lathering up, life, lure, motivating force, motivation, motive, motive power, occasion, payment, percentage, persuasive, perturbation, principle, profit, propellant, provocation, provocative, push, restorative, reward, spark plug, spur, steaming up, stimulant, stimulation, stimulative, stimulator, stirring, stirring up, sweetener, sweetening, tonic, urging, whet, whipping up, working up