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

To cause to draw near or adhere by physical force.

L. attractus, p.p. of attrahere "to draw, to attract," from ad- "to" + trahere "to pull, draw."

Darkašidan, from dar- "in, into" + kašidan "to draw, attract," → galaxy.

The act or capability of attracting. A physical force (gravitational, electric, magnetic, etc.) exerted by material bodies.

Attraction, n. from → attract.

Having the quality of attracting.

Verbal adj. from → attract.

A physical force (→ gravitational, → electric, → magnetic, etc.) by which a body attracts another.

→ attractive; → force.

The physical body that attracts. → Great Attractor.

→ attract; → -or.

An small → irregular galaxy undergoing → violent star formation activity. These objects appear blue by reason of containing clusters of hot, → massive stars which ionize the surrounding interstellar gas. They are chemically unevolved since their → metallicity is only 1/3 to 1/30 of the solar value. Same as → H II galaxy.

→ blue; → compact; → dwarf; → galaxy.

The factor e^-E/kT involved in the probability for atoms having an excitation energy E and temperature T, where k is Boltzmann's constant.

→ Boltzmann's constant; → factor.

The ability of a → liquid to → flow in a → narrow space, such as a thin → tube, without the assistance of, and in opposition to, external forces like → gravity. Also called → capillarity. It occurs because of intermolecular → attractive forces between the liquid and solid surrounding surfaces. If the diameter of the tube is sufficiently small, then the combination of → surface tension (which is caused by → cohesion within the liquid) and → adhesion (between the liquid and the → container) acts to lift the liquid. The capillarity of the liquid is high when adhesion is greater than cohesion. For example, water in a thin glass tube has strong → adhesive forces due to the hydrogen bonds that form between the water molecules and the oxygen atoms in the glass wall (made of → silica, SiO₂). In contrast, mercury is characterized by stronger cohesion, and hence its capillarity is much lower.

→ capillary; → action.

A point toward which a force on a body is always directed.

→ center; → attraction.

A succession of → nuclear fissions when the neutrons released by previous fissions produce other nuclear fissions which themselves cause other reactions and the reactions goes on increasing exponentially.

→ chain; → reaction.

1a) The aggregate of features and traits that form the individual nature of some person or thing.
1b) One such feature or trait; characteristic.
2) A person represented in a play, film, story, etc; role. See also → personage (Dictionary.com).
3) Computers: One of a set of symbols, such as letters or numbers, that are arranged to express information; the numerical code representing such a character.

M.E. carecter "distinctive mark," from O.Fr. caractère, from L. character, from Gk. kharakter "graving tool, its mark," from kharassein "to engrave," from kharax "pointed stick."

1, 2) Serešt "nature, temperament, constitution; mixed," sereštan "to mix, mingle; knead;" serišom "glue;" Mid.Pers. srištan "to mix, knead;" cf. Av. ham-sriš- "to put together;" Skt. śres- "to cling, stick, be attached;" Proto-Ir. root *sraiš- "to put together, attach" (Cheung 2007).
Sereštâr with -âr, contraction of âvar agent noun of âvardan "to bring; to cause, produce," → format.
3) Daxšé, variants dâq "a brand, a mark burned on the skin of an animal with a hot iron," Gilaki dajé "a brand," Hamadani daj "sign placed on a heap of harvest indicating identity or ownership," Mid.Pers. daxšag "mark, sign, charactersitic; (monthly) signs (of women)", dazidan "to burn, scorch," Av. daxša- "sign, mark, defect," from dag- "to burn," dažaiti "burns," cf. Skt. dah- "to burn," dahati "burns," Gk. tephra "ash," L. favilla "glowing ashes," Lith. dagas "hot season," O.Prus. dagis "summer," P.Gmc. *dagaz, Ger. Tag, E. day; PIE *dheg^wh- "to burn."

1a ) A distinguishing feature or quality.
1b) The integer part of a → common logarithm. For example, log₁₀ (23) = 1.362, where the characteristic is 1 and the → mantissa is 0.362.
2) Pertaining to, constituting, or indicating the character or peculiar quality of a person or thing; typical; distinctive.

→ character; → -istic.

Of a pulsar, a normalized period of rotation assumed to be a good approximation to pulsar's true age.

→ characteristic; → age.

Graph representing an optical film's response to the amount of light falling on it.

→ characteristic; → curve.

Physics: An analytical relationship between a set of physical variables that determines the state of a physical system.
Math.: The equation which is solved to find a matrix's eigenvalues, also called the characteristic polynomial.

→ characteristic; → equation.

A typical or most likely mass for the formation of an astronomical object. In current star formation models, it is of order of a few tenths of a → solar mass.

→ characteristic; → mass.

The quantity kT in the → Maxwell-Boltzmann distribution law, where k is → Boltzmann's constant and T the gas temperature. See also → thermal energy.

→ characteristic; → thermal; → energy

1) The act of describing the character or qualities of someone or something.
2) The artistic representation (as in fiction or drama) of human character or motives (Merriam-Webster.com).

→ characterize; → -tion.

1) To mark or distinguish as a characteristic; be a characteristic of.
2) To describe the character or individual quality of.
3) To attribute character to (Dictionary.com).

→ character; → -ize.

A → change or → transformation in which a → substance → decomposes, → combines with other → substances, or interchanges constituents with other substances.

→ chemical; → reaction.