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

In communications, the process of recovering the original information from a modulated signal wave. → modulation.

→ de- + → modulation

An imaginary intelligent entity introduced in several → thought experiments, such as → Laplace's demon and → Maxwell's demon.

From L. dæmon "spirit," from Gk. daimon "deity, fate, fortune."

Pari "a good genius, a fairy," from Mid.Pers. parîk "sorceress, witch;" from Av. pairikā- "sorceress, witch."

1) To make evident or establish by arguments or reasoning; prove.
2) To describe, explain, or illustrate by examples, specimens, experiments, or the like.
3) To manifest or exhibit; show.
4) T display openly or publicly, as feelings (Dictionary.com).

From L. demonstratus, p.p. of demonstrare "to show, point out," from → de- + monstrare "to show," from monstrum "sign, portent."

Padišidan, from Sogd. padēš "to show," ultimately from Proto-Ir. *apa-dais-, from *dais- "to show," cf. Av. daēs- "to show," related to andiš, → think.

1) The → act or → circumstance of proving or being → proved conclusively, as by → reasoning or a show of → evidence.
2) Something serving as → proof or supporting evidence.
3) An exhibition, as of feeling; display; → manifestation (Dictionary.com).

Verbal noun of → demonstrate.

A person or thing that demonstrates (Dictionary.com).

→ demonstrate; → -or.

The removal of mystery or confusion surrounding a topic or idea.

→ demystify; → -tion.

The second brightest star, of magnitude V = 2.14, in the constellation → Leo. A → main sequence star of → spectral type A3 V.

Denebola, from Ar. dhanab al-asad (ذنب الاسد) "tail of the lion," referring to the lion in Gk. mythology.

Širdom "tail of the lion," from šir "lion" → Leo + dom "tail," → comet. Zanab-ol-asad from Ar., as above.

1) A name or designation.
2) The action of naming or classifying something. 3) One of the grades or degrees in a series of designations of quantity, value, measure, weight, etc. (Dictionary.com).

Verbal noun of → denominate.

→ core mass function.

→ dense; → core; → mass; → function.

In the early Universe, localized enhancements in the density of either matter alone or matter and radiation. According to models, very small initial fluctuations (less than 1 percent) can lead to subsequent formation of galaxies.

→ density; → fluctuation.

An → H II region which lacks enough matter to absorb all → Lyman continuum photons of the → exciting star(s). In such an H II region a part of the ionizing photons escape into the → interstellar medium. See also → ionization-bounded H II region.

→ density; → bounded; → region.

General: The act or process of depleting. The state of being depleted.
Astro.: The process or state of a material which contains less of a particular chemical element or isotope than the expected standard amount.

Noun from → deplete

The region of a semiconductor in which the density of mobile carriers is too low to neutralize the fixed charge density of donors and acceptors.

→ depletion; → layer.

The time it takes for a given → chemical species to be reduced below a significant level of → abundance in a → compound or → object.

→ depletion; → time.

Reducing or randomizing the polarization of an electromagnetic wave, by transmission through a non-homogeneous medium or a depolarizer.

from → de- + → polarization.

The action of deporting an alien from a country.

→ deport; → -tion.

The process by which water vapor changes directly to ice without first becoming a liquid. This is how snow forms in clouds, as well as frost and hoar frost on the ground. The opposite of deposition is → sublimation. → condensation.

M.E., from O.Fr. deposition, from L. deposition- "putting aside, testimony, burial," from deposit(us) "laid down," p.p. of deponere "to put down," from → de- + ponere "to put, place."

Vâneheš, from vâ-→ de- + neheš verbal noun of nehâdan "to put, place," Mid.Pers. nihâtan, O.Pers./Av. ni- "down; into," → ni-, + dā- "to put; to establish; to give," dadāiti "he gives," cf. Skt. dadâti "he gives," Gk. didomi "I give," L. do "I give;" PIE base *do- "to give."

An act of attacking or plundering.

→ de-; → predation.

1) Navigation:→ dip.
2) Meteorology: An area of low atmospheric pressure.
3) Geology: An area of the Earth's crust sunken or depressed below the surrounding area, formed by various mechanisms.

Depression, verbal noun of depress, from O.Fr. depresser, from L.L. depressare, frequentative of pressus, p.p. of deprimere "press down," from → de- "down" + premere "to press."

1) Našib-e ofoq, from našib "declivity, descent; lowness of ground, slope of any place" (Mid.Pers. nišēp "declivity, (astrology) dejection," Av. *nixšvaēpā-, xšvaēpā- "bottom, rear") + ofoq→ horizon. 2) Forubâr, from foru "down, downward; below; beneath," → de- + bâr "load, pressure, charge," → charge. 3) Našiblâx, from našib, as above, in item 1, + -lâx place suffix.

1) General: The act or fact of deriving or being derived; origin; descent.
2) Math.:→ differentiation; development of a theorem.
3) Grammar: The formation of a word from another word or base. It typically occurs by the addition of an affix.

Verbal noun of → derive.