stability

(stə-bĭl'ĭ-tē)
n., pl., -ties.

1. The state or quality of being stable, especially:
   1. Resistance to change, deterioration, or displacement.
   2. Constancy of character or purpose; steadfastness.
   3. Reliability; dependability.
2. The ability of an object, such as a ship or aircraft, to maintain equilibrium or resume its original, upright position after displacement, as by the sea or strong winds.
3. Roman Catholic Church. A vow committing a Benedictine monk to one monastery for life.

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noun

1. The condition of being free from defects or flaws: durability, firmness, integrity, solidity, soundness, strength, wholeness. See better/worse.
2. Reliability in withstanding pressure, force, or stress: fastness, firmness, hardness, security, soundness, stableness, steadiness, strength, sturdiness, sureness. See better/worse, change/persist, continue/stop/pause.

n

Definition: resistance of some degree
Antonyms: insecurity, instability, unsteadiness, variability, wavering

The state of a parcel of air which, if displaced vertically, will return to its original position. Thus, if a parcel of air cools more on rising than the air which surrounds it, it becomes denser than its surroundings and therefore sinks.

The atmosphere is absolutely stable when the environmental lapse rate is less than both the dry and saturated adiabatic lapse rates. Atmospheric stability is reinforced by inversions.

The resistance of a structure or element thereof to withstand sliding, overturning, buckling, or collapsing.

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1. Tendency of an object to maintain its resting position or maintain a constant linear velocity or angular velocity. Factors affecting stability include the mass and height of the object, and the position, size, and shape of its supporting base. The stability of an object is inversely related to the height of its centre of gravity above its supporting base. The object tends to be more stable as its line of gravity falls closer to the centre of the base of its support. The further one part of the object moves away from the line of gravity, the less stable the object will he unless another part of the object makes compensatory movements. The stability of an object in motion is directly proportional to its momentum, See also equilibrium;

2. See joint stability.

3. In groups, the turnover rate for group-membership, and the length of time members of a group have been together. High stability is associated with high cohesion.

4. A dimension of causal attribution theory that extends from stable to unstable, indicating whether the attributions are liable to change or remain unchanged. Athletes tend to attribute stable factors (such as level of ability) to expected outcomes, and unstable factors (such as luck) to unexpected outcomes.

Resisting being heeled over or capsized by wind and wave
When we talk of stability in a boat, we mean her resistance to being inclined or her tendency to return to an upright position after having been heeled. That kind of stability is known as form, or initial, stability because it is derived largely from the form or shape of the immersed hull. A boat that greatly resists being heeled is called stiff; a boat that heels easily is said to be tender, or crank.But you will often hear reference to another kind of stability called ultimate stability, which is a boat’s ability to right herself from a 180-degree capsize. Paradoxically, good form stability often results in poor ultimate stability. The reason is that form stability is mostly derived from wide beam. A beamy, shallow-hulled sailboat feels comfortingly resistant to capsize. When you step aboard, she hardly heels— and when the wind blows hard, she hardly leans over. But if she is capsized by a wave, her beam will keep her upside down for an excessively long time, perhaps long enough to sink her. The point is that beam contributes to stability both in the upright and the inverted positions.

Hydrostatic stability curves for a Contessa 32 footer and the Half-Tonner Grimalkin in still water. These two boats, similar in length but different in hull shape, displacement, and position of the center of gravity, have different stability characteristics; this is particularly true of their ranges of positive (safe) and negative (dangerous) stability.

It’s another paradox of naval architecture that the beamier and more stable a boat appears to be in calm water, the more unstable she appears to be in a seaway. Her wide beam creates a long lever that makes it easier for each passing wave to lift her, and her response even to small waves will be rapid and jerky.Whereas initial stability comes from wide beam and keel weight, ultimate stability derives mainly from reasonably narrow beam and a low center of gravity—that is, a deep, narrow boat. Such a boat may lack the form stability of a beamier boat and may heel more initially in a breeze—at least until her ballast keel starts to have some effect— but she will also be unstable in the inverted position and will, therefore, roll herself upright very promptly.Obviously, ultimate stability is not of great importance if you always sail your boat in sheltered waters, but if you plan to go to sea, there is always a chance that a wave will capsize you.Big boats are better than small boats in this respect, because the initial stability increases with size. The overturning moment varies with the cube of a boat’s length, whereas stability varies with the fourth power of her length. Nevertheless, any boat may be turned turtle by a breaking wave with a height of 55 percent of her overall length.Stability is an important part of seaworthiness, but it’s not the prime agent, according to eminent research scientist and smallboat sailor Tony Marchaj. “Sea-worthiness is in fact profoundly affected by a number of interacting factors other than mere stability,” he says.One of those factors is inertia, which is largely responsible for the renowned seaworthiness of some fairly narrow sailing yachts that many people might be tempted to dismiss as being too tender.In powerboats, as in sailboats, the height of the center of gravity is the final arbiter of ultimate stability, and the center of gravity will be lowest in a displacement powerboat with a comparatively narrow, deep hull and its engine(s) and tankage carried as low as possible. The center of gravity will be higher— up near the top of the engines— in an express sportfisherman; in a planing powerboat with its wide, shallow hull, the center of gravity will be well above the waterline.The hull shape of the planing powerboat gives it high form stability, so it will feel more stable than the more rolling displacement hull—particularly because, at speed, it derives dynamic stability from the hydrodynamic lift its hull form generates. But this is deceptive: whereas a displacement trawler might retain positive stability to a roll angle of 130 degrees—up in seaworthy keel-sailboat territory—a planing powerboat will have an ultimate stability of about 45 degrees or less.See also Capsize; Hull Shapes; Inertia; Keels; Seaworthiness; Stability Limits.

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Quotes:

"Every time I try to define a perfectly stable person, I am appalled by the dullness of that person." - J. D. Griffin

i. The ability of an aircraft to return to the same particular condition of flight after having been disturbed from that condition, without any effort on the part of the pilot. The illustration indicates how a stable aircraft returns to its level flight attitude once it is disturbed for any reason.



ii. A state of atmosphere in which the vertical distribution of temperature is such that a parcel of air will resist displacement from its initial level.



Atmospheric stability.

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The property that refers to the nature of a substance or of a mixture of two or more substances as defined by a specified criteria. Flavor stability would refer to how long it takes for a flavor's strength and flavor character to noticeably depreciate over time. See Shelf-Life Stability, Quality Assurance.

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n

The quality of being physically or emotionally predictable, orderly, not readily moved.

For a list of words related to stability, see:

• Chemical Properties and Reactions - stability: resistance of a substance to decomposition or disintegration

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See words rhyming with "stability."

This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)

Dansk (Danish)
n. - stabilitet, fasthed, standhaftighed, stadighed

Nederlands (Dutch)
evenwichtigheid, stabiliteit, bestendigheid

Français (French)
n. - (gén) stabilité, constance, (Chim) stabilité

Deutsch (German)
n. - Stabilität

Ελληνική (Greek)
n. - ευστάθεια, σταθερότητα, ισορροπία

Italiano (Italian)
stabilità, fermezza

Português (Portuguese)
n. - estabilidade (f)

Русский (Russian)
устойчивость, прочность семейных отношений, постоянство, прочность, остойчивость

Español (Spanish)
n. - equilibrio, estabilidad, firmeza, entereza

Svenska (Swedish)
n. - stabilitet, stadga, stadighet, fasthet, soliditet

中文（简体）(Chinese (Simplified))
稳定, 稳定性, 坚定, 安定, 恒心

中文（繁體）(Chinese (Traditional))
n. - 穩定, 穩定性, 堅定, 安定, 恆心

한국어 (Korean)
n. - 안정, (로마 카톨릭) 정주 서원, 복원성

日本語 (Japanese)
n. - 安定, 安定性, 強固さ

العربيه (Arabic)
‏(الاسم) استقرار, ثبات, رسوخ, توازن‏

עברית (Hebrew)
n. - ‮יציבות‬

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