An Etymological Dictionary of Astronomy and Astrophysics
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A disk that would form around a star when the star injects matter into a close orbit. This is in contrast to an → accretion disk, which transfers matter from outside to the star. The mass gets injected into the decretion disk by a not yet well-known mechanism, most probably a combination of → non-radial pulsation, fast rotation, and possibly small-scale → magnetic fields. See also → viscous decretion disk.

→ decretion; → disk.

The process of restoring encrypted data back to the original information. See also → encryption and → decoding.

→ decrypt; → -tion.

1) The act or process of deducting; something that is or may be deduced.
2) A process of reasoning in which a conclusion is derived from the premises presented without a need for additional information. → deductive reasoning.

Verbal noun from → deduce.

Reasoning from the → general to the → particular (or from → cause to → effect).

→ deductive; → reasoning.

1) The act or process of establishing some value or condition with precision.
2) The formal statement of the meaning or significance of a word, concept, etc.
3) Optics: The clarity, fidelity, sharpness, and brilliancy of an image formed by an optical system.

Verbal noun of → define.

A rapid → chemical reaction in which the → output of → heat is enough to enable the reaction to proceed and be accelerated without input of heat from another source. The effect of a true deflagration under confinement is an → explosion. See also: → detonation; → explosion.

Verbal noun of → deflagrate.

The act or state of deflecting or the state of being deflected. Amount of deviation.
Electronics: In a cathode-ray tube, the bending, by a magnetic field, of the beam of electrons after the focused beam leaves the electron gun.

Verbal noun of → deflect.

1) The angle by which a light ray is curved by the gravitational field of a massive body. Einstein's general relativity predicts that a light ray which tangentially grazes the surface of the Sun is deflected by 1''.7. This result was confirmed in 1919 when the apparent angular shift of stars close to the limb of the Sun was measured during a total solar eclipse.
2) In a cathode-ray tube, the angle through which the beam is bent, vertically, horizontally, or diagonally.

→ deflection; → angle.

The bending of a light ray under the gravitational effect of a massive body. → deflection angle.

→ deflection; → light.

Altering in the size or shape of a body. See also → deformable.

Verbal noun of → deform.

The process of producing a quantifiable result in a → fuzzy logic system, given → fuzzy sets and corresponding → membership functions. Defuzzification is the last step in a fuzzy logic system. After → fuzzy inferencing, the overall result is a → fuzzy value. This result should be defuzzified to obtain a final → crisp value.

Verbal noun of → defuzzify; → -tion.

The number of electrons a neutral atom has lost in an ionizing physical process (radiation, shock, collision). In spectroscopy, the degree of ionization is indicated by a Roman numeral following the symbol for the element. A neutral atom is indicated by the Roman numeral I, a singly ionized atom, one which has lost one electron, is indicated by II, and so on. Thus O VI indicates an oxygen atom which has lost five electrons.

→ degree; → ionization.

The ratio of the intensity of polarized portion of light to the total intensity at a point in the beam.

→ degree; → polarization.

The act or process or an instance of dehumanizing.

Verbal noun of → dehumanize.

Chemistry: A process in which all charged species are removed from a solution.
The return of an ionized gas to its non-ionized state after the ionizing source has been removed.

From → de- + → ionization.

Neutrons resulting from nuclear fission which are emitted with a measurable time delay. Delayed neutrons are responsible for the ability to control the rate at which power can rise in a reactor. → prompt neutrons.

Delayed, p.p. of the verbal form of → delay; → neutron.

A mechanism predicted by theoretical models of → supernova explosion that operates after the → supernova shock fails to deliver a → prompt supernova explosion. The delayed supernova explosion mechanism assumes that a few tenth of a second after the → iron core collapse, the supernova shock is stalled due to energy dissipation. The material between the → protoneutron star and the stalled shock is mainly disintegrated into neutrons and protons due to the high temperatures (a few MeV) in this region. As the → neutrinos coming from the protoneutron star run through this material, a fraction of the neutrinos are captured by the → nucleons, and their energy is deposited in the material. As a result, the material behind the shock is heated by the neutrinos. If this neutrino heating is efficient enough, the stalled shock can be reinvigorated to bring about a supernova explosion.

→ delay; → supernova; → explosion.

1) An act or instance of deleting. The state of being deleted. A deleted word, passage, etc.
2) Genetics: A type of chromosomal aberration in which a segment of the chromosome is removed or lost (Dictionary.com).

Verbal noun from → delete.

Same as → Dirac function.

Same as → Mintaka.

→ delta; → Orion.