An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

A suffix denoting several senses, including state or condition, devotion or adherence, principle, doctrine, act, process.

From Gk. -ismos, -isma noun suffixes, often directly, often through L. -ismus, -isma, sometimes through Fr. -isme, Ger. -ismus (all ultimately from Gk.); → -ist.

Voluntary non attendance at work, without valid reason. Absenteeism means either habitual evasion of work, or willful absence as in a strike action. It does not include involuntary or occasional absence due to valid causes, or reasons beyond one's control, such as accidents or sickness (BusinessDictionary.com).

→ absent; → -ism.

1) The doctrine or practice of vigorous action or involvement as a means of achieving political or other goals, sometimes by demonstrations, protests, etc. (Dictionary.com). See also → activist.
2) Philosophy: a) A theory that the essence of reality is pure activity, especially spiritual activity, or process. b) A theory that the relationship between the mind and the objects of perception depends upon the action of the mind (Dictionary.com).

→ active; → action; → -ism.

→ prism angle.

→ angle; → prism.

In an imaging system, the dependence of its performance on field angle. In other words, the spatial variability of the → point spread function for off-axis sources.

→ an- + → isoplanatism.

A property possessed by some → metals, → alloys, and salts of transition elements in which there is a lack of → magnetic moment due to the antiparallel or spiral arrangement of atomic → magnetic moments.

→ anti- + → ferromagnetism.

A unique Greek geared device, constructed around the end of the second century BC to display the movement of the Sun, the Moon, and possibly the planets around the Earth, and predict the dates of future eclipses. It measures about 32 by 16 by 10 cm and contains at least 30 interlocking gear-wheels, all of them having triangular teeth, from 15 to 223 in number. This device is one of the most stunning artefacts remained from antiquity, revealing an unexpected degree of technical creativity for the period. Nothing close to its technological sophistication appears again for well over a millennium, when astronomical clocks appear in the medieval Europe. It was discovered in 1901 in a sunken ship just off the coast of Antikythera, an island between Crete and the Greek mainland. Its significance and complexity were not understood until decades later. After lots of study involving several research fields, a copy of the device has recently been constructed. See, e.g., Freeth et al. 2006, Nature 444, 587.

Named after the Greek island in the Ionia Sea from which the fragments of the device were discovered in 1901 by sponge divers, who found a sunken Roman ship. Several pieces of evidence indicate that the Roman ship carrying the device wrecked sometime shortly after 85 BC. The ship also contained an enormous booty of bronzes, glassware, jewelry and pottery; → mechanism.

Freedom from spherical aberration and coma.

Aplanatism, from aplanatic, from a- "negation prefix" + Gk. plane "wandering," from planasthai "to wander" + -tic adjective-forming suffix.

Nâbirahi, from nâ- "negation prefix" + birah "a devious path; a wanderer, who deviates, errs," + -i noun affix.

The capacity of an optical system to bring three widely separated wavelengths of light into a single focus.

→ apochromatic; → -ism.

A group of stars in the sky which are traditionally imagined to present a pattern within a → constellation. Examples include the → Big Dipper, the → Northern Cross, the → Square of Pegasus, and → Orion's Belt.

Gk. asterismos "a marking with stars, constellation," from aster, → astro- + → -ism.

Axtargân, from axtar "star" → astro- + -gân suffix denoting collective nature.

Of or relating to → asteroseismology.

→ spectropolarimetry; → -ic.

The study of the → internal structure of stars through the interpretation of their pulsation periods (→ stellar pulsation). The radial pulsations are the result of → sound waves resonating in the stars interior. Different → pulsation modes penetrate to different depths inside a star. If a large number of pulsation modes occurs, then the stellar interior, which is not directly observable, can be probed from oscillation studies because the modes penetrate to various depths inside the star. Using a complex mathematical analysis, very detailed investigations of the structure of the star's interior can be carried out. Applied to the Sun, it is called → helioseismology.

From → astero- "star," from aster-, → astro-, + → seismology.

Axtarlarzešenâsi, from axtar "star," → astro-, + larzešenâsi, → seismology.

1) An imperfection in an optical system whereby light from a point source is formed into an image as a straight line, ellipse, or circle. The rays of light in two perpendicular planes appear as two lines at right angles.
2) A common eye defect in which the unequal curvature of one or more refractive surfaces of the eye, usually the cornea, prevents light rays from focusing clearly at one point on the retina, resulting in blurred vision.

From astigmatic, from Gk. → a- "without" + stigmatos, from stigma "a mark, spot, puncture."

1) Nâgerâvari, from nâ- "without, un" + gerâ, stem of gerâyidan "to converge," + -var, agent forming suffix, + -i, noun forming suffix.
2) The same as above with -bini "seeing, discerning".

1) The doctrine or belief that there is no → God.
2) Disbelief in the existence of a supreme being or beings.

→ a-; → theism.

1) The enforcement or advocacy of strict obedience to authority at the expense of personal freedom.
2) Lack of concern for the wishes or opinions of others (OxfordDictionaries.com).

→ authoritarian; → -ism.

An → isomorphism between an → object and itself.

→ auto-; → morphism.

Same as → isomorphism.

→ bijective; → morphism.

A white, crystalline, brittle metallic chemical element with a pinkish tinge; symbol Bi. → Atomic number 83; → atomic weight 208.9804; → melting point 271.3°C; → boiling point about 1,560°C; → specific gravity 9.75 at 20°C; → valence +3 or +5. Bismuth is the most → diamagnetic of all metals. Its thermal conductivity is lower than any metal, except → mercury. There is only one naturally occurring → isotope of bismuth, ²⁰⁹Bi. Bismuth is used in a number of very different applications, chiefly in bismuth alloys, and in pharmaceuticals and chemicals.

From Ger. Bismuth, Wismut, Wissmuth, probably from weisse Masse "white mass," indicating how the element appears in nature.

The mechanism that accounts for the → bistability jump.

→ bistability; → mechanism.

A mechanism aimed at explaining the → disruption of a → binary system. As one component loses mass dramatically, the resulting loss of → gravitational attraction changes the orbit of, or ejects completely, the → companion star.

Adriaan Blaauw (1914-2010), 1961, Bull. Astron. Inst. Netherlands 15, 265; → mechanism.