threshold

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threshold

 [thresh´old]
1. the level that must be reached for an effect to be produced, as the degree of intensity of stimulus that just produces a sensation.
2. that value at which a stimulus just produces a sensation, is just appreciable, or comes just within the limits of perception.
auditory threshold the slightest perceptible sound.
threshold of consciousness the lowest limit of sensibility; the point of consciousness at which a stimulus is barely perceived.
defibrillation threshold DFT; the minimum amount of energy in joules that will consistently terminate ventricular fibrillation.
fibrillation threshold the least intensity of an electrical impulse that will cause cardiac tissue to begin fibrillation.
pacing threshold the minimal electrical stimulus required to produce consistent cardiac depolarization.
renal threshold that concentration of a substance (threshold substance) in plasma at which it begins to be excreted in the urine.
sensing threshold in cardiac pacing terminology, the voltage of the minimum signal that consistently activates pulse generator function.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

thresh·old

(thresh'ōld), Avoid the misspelling/mispronunciation threshhold.
1. The point at which a stimulus first produces a sensation.
2. The lower limit of perception of a stimulus.
3. The minimal stimulus that produces excitation of any structure, for example, the minimal stimulus eliciting a motor response.
Synonym(s): limen (2) [TA]
[A.S. therxold]
Farlex Partner Medical Dictionary © Farlex 2012

threshold

(thrĕsh′ōld′, -hōld′)
n.
The point that must be exceeded to begin producing a given effect or result or to elicit a response: a low threshold of pain.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

threshold

Medtalk The point, stage, or degree of intensity at which a particular effect occurs or action is taken. See Therapeutic threshold, Transfusion threshold.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.

thresh·old

(thresh'ōld)
1. The level of intensity at which a stimulus first produces a sensation.
2. The lower limit of perception of a stimulus.
3. The minimal stimulus that produces excitation of any structure.
4. Synonym(s): limen.
[A.S. therxold]
Medical Dictionary for the Health Professions and Nursing © Farlex 2012

threshold

the level at which a STIMULUS results in a response and below which there is no response despite the application of a stimulus.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005

threshold 

The value of a stimulus that just produces a response. Syn. limen.
absolute threshold The minimum luminance of a source that will produce a sensation of light. It varies with the state of dark adaptation, the retinal area stimulated, the wavelength of light, etc. Syn. light threshold. See photochromatic interval.
contrast threshold See differential threshold.
corneal touch threshold See corneal touch threshold.
differential threshold The smallest difference between two stimuli presented simultaneously that gives rise to a perceived difference in sensation. The difference may be related to brightness, but also to colour and specifically to either saturation (while hue is kept constant) or hue (while saturation is kept constant). The differential threshold of luminance is equal to about 1% in photopic vision. Syn. contrast threshold (if the difference is one of luminance); just noticeable difference (jnd). See Weber's law; contrast sensitivity.
light threshold See absolute threshold.
movement threshold 1. The minimum motion of an object that can be perceived. 2. The speed at which an object moving between two points just appears to be moving. See hyperacuity; phi movement.
resolution threshold See limit of resolution.
stereo-threshold See stereoscopic visual acuity.
Millodot: Dictionary of Optometry and Visual Science, 7th edition. © 2009 Butterworth-Heinemann

thresh·old

(thresh'ōld) Avoid the misspelling threshhold.
1. Point at which a stimulus first produces a sensation.
2. Lower limit of perception of a stimulus.
[A.S. therxold]
Medical Dictionary for the Dental Professions © Farlex 2012
References in periodicals archive ?
The Eugene-Springfield area, however, had already crossed that threshhold last week, with prices climbing to $4.02 per gallon.
In a review of police pay and conditions commissioned by the Government, Tom Winsor, a former rail regulator, recommended that the "discredited" SSP payments should be scrapped, along with all competence-related threshhold payments.
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Over the threshhold: A married couple heading off for their honeymoon.
The Zurich-based bank is lowering the threshhold for bonuses to be deferred to CHF50,000 (USD51,845) as against CHF125,000 paid out in cash previously.
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It is not just the first prize which has suffered - the quarterand semi-finals are now, like the first round heats, worth pounds 100 to the winners compared to pounds 150 and pounds 200 respectively 12 months ago, although all races do qualify for Trainers' Championship points despite being under the usual pounds 150 threshhold due to the competition's Category One status.
The World Professional Association for Transgender Health says the threshhold should be 18, as does Sweden, which pioneered sex-change legislation; however Sweden provides young transsexuals with reversible hormone treatment before that.
Aid rises with the level of local commitment, but Veillon concedes that the lower threshhold is high: "That reduces the potential because a lot of international productions don't come for 50% of their shoot."
There has been so much public objection to this item, that the manufacturers of the vaccine have reduced the amount per dose below the threshhold where it must appear on the label, but have not removed it.
John Michie takes centre stage when DI Robbie Ross finds a baby on a doorstep and a body over the threshhold.