• WordNet 3.6
    • n perturbation the act of causing disorder
    • n perturbation a disposition that is confused or nervous and upset
    • n perturbation activity that is a malfunction, intrusion, or interruption "the term `distress' connotes some degree of perturbation and emotional upset","he looked around for the source of the disturbance","there was a disturbance of neural function"
    • n perturbation (physics) a secondary influence on a system that causes it to deviate slightly
    • n perturbation an unhappy and worried mental state "there was too much anger and disturbance","she didn't realize the upset she caused me"
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Webster's Revised Unabridged Dictionary
    • Perturbation (Astron) A disturbance in the regular elliptic or other motion of a heavenly body, produced by some force additional to that which causes its regular motion; as, the perturbations of the planets are caused by their attraction on each other.
    • Perturbation The act of perturbing, or the state of being perturbed; esp., agitation of mind.
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Century Dictionary and Cyclopedia
    • n perturbation The act of perturbing, or the state of being perturbed; disturbance; disorder; especially, disquiet of mind; restlessness or want of tranquillity of mind; commotion of the passions.
    • n perturbation Variation; especially, irregular or violent variation.
    • n perturbation A cause of disquiet.
    • n perturbation In astronomy, a deviation of the motion of a planet or comet from a fixed orbit or from its regular velocity in that orbit. Perturbations are caused by the gravitating action of bodies other than the primary or central body. They are commonly and conveniently conceived, not as drawing the planets out of their orbits, but as consisting in gradual changes of the elements of the orbits themselves. All perturbations due to gravitation are, strictly speaking, periodical. But some of them, which depend upon the relative situation of the orbits of different planets, go through their changes in such vast intervals of time that they are more conveniently regarded as progressive and not periodic, and are termed secular perturbations; while others, depending for the most part upon the relative situations of the planets in their orbits, go through their changes in comparatively short intervals of time, and can only be represented as periodic, and these are technically called the periodic inequalities.
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Chambers's Twentieth Century Dictionary
    • ns Perturbation act of perturbing or state of being perturbed: disquiet of mind: irregular action, esp. (astron.) the disturbance produced in the simple elliptic motion of one heavenly body about another by the action of a third body, or by the non-sphericity of the principal body
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Webster's Revised Unabridged Dictionary
L. perturbatio,: cf. F. perturbation,
Chambers's Twentieth Century Dictionary
Fr.,—L. perturbāre, -ātumper, thoroughly, turbāre, to disturb—turba, a crowd.


In literature:

His very lack of perturbation added weight to the statement.
"The Bat" by Avery Hopwood
Soames' perturbation was so great on that occasion that he feared it must unfailingly be noticed.
"The Yellow Claw" by Sax Rohmer
Moze was lying down, but the others were whining and howling in a state of great perturbation.
"The Last of the Plainsmen" by Zane Grey
When the men did not gamble something immediate and perturbing was on their minds.
"To the Last Man" by Zane Grey
Michael meantime had been travelling down from London without perturbing himself over the scene with his father which he knew lay before him.
"Michael" by E. F. Benson
And at the roots strange poisonous flowers lie writhing in perturbed slumber.
"The Works of Edgar Allan Poe Volume 2 (of 5) of the Raven Edition" by Edgar Allan Poe
The minds of the people are perturbed.
"China and the Manchus" by Herbert A. Giles
After a while he walked off to his wife's room, still perturbed in spirit.
"The Prime Minister" by Anthony Trollope
Mrs. Mumpson sank back in her chair, but her mode of rocking betokened a perturbed spirit.
"He Fell in Love with His Wife" by Edward P. Roe
When she heard this, Grace Carter, the wife of Major Carter, one of the surgeons at the Ancon Hospital, was greatly perturbed.
"The Lost Road" by Richard Harding Davis

In poetry:

Its grasses by the top;
The rains thereon that drop
With drip acerb
"To The Dead Cardinal Of Westminster" by Francis Thompson
An agitation of the air,
A perturbation of the light
Admonished me the unloved year
Would turn on its hinge that night.
"End Of Summer" by Stanley Kunitz
How I am pleased with thee, sweet girl! But do
Shake off this perturbation, be not anxious,
Be not alarmed, I want to hear thee talk -
Be cheerful.
"Nathan The Wise - Act V" by Gotthold Ephraim Lessing
These perturbations, this perpetual jar
Of earthly wants and aspirations high,
Come from the influence of an unseen star,
An undiscovered planet in our sky.
"Haunted Houses. (Birds Of Passage. Flight The First)" by Henry Wadsworth Longfellow
All summer cannot quicken it with heat,
Nor Spring perturb it with a budding bough,
Nor all the glittering devils of the sleet
In snowing Winter rack its quiet now.
"The Golden Corpse" by Stephen Vincent Benet
"To-day my soul clasps Form; but where is my troth
Of yesternight with Tune: can one cleave to both?"
- "Be not perturbed," said she. "Though apart in fame,
As I and my sisters are one, those, too, are the same.
"Rome: The Vatican-Sala Delle Muse." by Thomas Hardy

In news:

Researchers Provide Systems-Level Dissection of Regulatory Perturbations in Cancer.
A worried-looking Demi Moore looks perturbed in between takes on the set.
Kinases have been the target of extensive research, and there has been significant interest in developing assays that measure the endogenous activities of kinases and their perturbation by small molecules.
At one heated point in Monday night's South Carolina Democratic debate, a perturbed Barack Obama finally blurted out to Hillary Clinton what millions of others have been thinking these past weeks.
And an internationally acknowledged expert on the applied- mathematics technique known as perturbation, died April 17 at Albany Medical Center Hospital.
You know the one — full-sized American steel with a low-profile tow rack in the bed, the claws of which protrude out of the tailgate like a perturbed crab looking to pinch pinch a car.
Perturbations to their structures caused by mysterious rocketing objects.
Those perturbations tip the researchers that a sunspot is forming.
Those perturbations are what tip the researchers that a sunspot is forming.
Our company recently implemented a policy that has quite a few people perturbed, myself included.
I was both pleased and perturbed by the "On the Runway" story in the Sunday New York Times Style section on January 30th.
Preseason or not, there's nothing easier to predict than Rick Carlisle being perturbed after a poor defensive performance.
NBA Playoff primer, plus a pick that might perturb you.
Baseball Stadiums' Peanut -Free Seating Perturbs Some Fans.
Councilmember Daniel Dromm says he is perturbed by the pigeon poop problem casting a shadow over the 74th Street station on Roosevelt Avenue, which hosts the No.

In science:

Substituting the above form of the perturbed variables into eqs.(1-3) and combining the resulting velocity field and the perturbed continuity equation in the slow mode limit (ω << Ω), we get an implicit relation between the perturbing potential and the perturbed surface density of the disc.
Low frequency m=1 normal mode oscillations of a self-gravitating disc
The expansion up to second order in the linear perturbations of the action (81) is useful to obtain the classical equations of motion for the perturbations and to calculate the spectra of the primordial perturbations generated during inflation, as we have seen in the previous section for a single scalar field.
Early Universe: inflation and cosmological perturbations
In discussing perturbative predictions for high-energy colliders, it is important to remember that non-perturbative effects can often be as large as higher-orders of perturbation theory.
Moriond 2009, QCD and High Energy Interactions: Theory Summary
The continuous production of perturbations around an inflating FLRW background is a decidedly quantum phenomenon: any classical perturbations are diluted away during inflation, while perturbations of quantum origin can develop a non-zero super-Hubble amplitude.
Primordial Fluctuations in String Cosmology
The physics that drives the rise in activity is a combination of the non-perturbative total pp cross-section; the non-perturbative physics of beam remnants, diffraction, and multiple partonic scattering; and perturbative low-pT QCD scattering.
THE TOOLS AND MONTE CARLO WORKING GROUP Summary Report from the Les Houches 2009 Workshop on TeV Colliders