-ation, -ization (-iz[e] + -ation); -isation (British spelling variation)

1. A small change in a physical system: A perturbation most often takes place when the equilibrium is disturbed from the outside.
2. A cause of mental disquiet, disturbance, or agitation: Tim's bizarre haircut was the perturbation that upset his parents at Easter dinner.
3. Variation in a designated orbit, as of a planet, that results from the influence of one or more external bodies: Gravitational attraction between planets can cause perturbations and cause a planet to deviate from its expected orbit.

Perturbations in Neptune's orbit led to the discovery of the object that was causing the perturbation, the planet Pluto.

Perturbations in the orbits of stars have led to the discovery of planetary systems outside of our Solar system.

The heating of a liquid within a dialyzing bag suspended over a hot plate: "The pervaporation of a liquid results in quick evaporation through the membrane; any colloids in solution remain within the bag while crystalloids (bodies that in solution can pass through a semipermeable membrane) diffuse out and crystallize on the outer surface of the bag (perstillation)."

"Colloids are two-phase systems in which one is uniformly dispersed in another as particles small enough so they cannot be filtered or will not settle out."

To publish something.

1. A process of fossilization during which dissolved inorganic material replaces the original organic contents: A petrification produces a stony substance that results in what appears to be something as hard as a rock.

Since the petrification of a snail that she found was complete and perfect, Sharon decided to save it and put it into her collection of other fossils.

2. A condition of utmost fear, causing a person to be unable to move: Jane was in a state of petrification and completely devastated after receiving the news of the tragic accident in which her father was killed.
3. The process of fossilization: Petrification is a geological process of preservation that turns organic material into a rock and usually takes millions of years to accomplish.

A rupture or tearing and of the lens.

The act or process of uttering with a voice; the production of phones or speech (vocal) sounds.

The use of a phonocatheter for the detection of sounds produced by the circulatory system. An intracardiac phonocatheterization, for example, consists of the passage of a phonocatheter into a chamber of the heart for the detection of sounds as an aid in the diagnosis of cardiac defects.

A procedure in which tissue is destroyed by using a light beam; such as, a laser.

Condensation of protein material by the controlled use of an intense beam of light: Photocoagulation is used especially in the treatment of retinal detachment and the destruction of abnormal retinal vessels, or of intraocular tumor masses.

Photocoagulation is a technique that uses intense light energy, as from a laser, to produce scar tissue used in treating certain eye disorders, in medical and biological research, etc.

The decomposition of a substance resulting from the action of light.

1. The oxidation of carbohydrates in plants with the release of carbon dioxide during photosynthesis.
2. A process in which an organism takes in oxygen and releases carbon dioxide in the presence of light, occurring during photosynthesis in conditions in which there is a low concentration of carbon dioxide and intensive levels of light.

A condition in which the skin reacts abnormally to light, especially ultraviolet radiations or sunlight: Photosensitization can be caused by the presence of drugs, hormones, or certain diseases, such as lupus, a chronic inflammatory ailment.

1. The formation of a permanent froth when a liquid is shaken together with a gas.
2. Etymology: from physallis, "bubble".