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

In astrophysics, a gaseous sphere in hydrodynamic equilibrium in which the pressure and density are related by the equation P = Kρ^(n+1)/n at each point along the radius, where K is a constant and n is the → polytropic index. The constant K depends upon the nature of the polytrope. Before the advent of computing technology, the theory of polytropes played an important role in physically modeling the structure of stars. → Lane-Emden equation.

Polytrope, from → poly- + trope, from → -tropic.

Bolgašt, from bol-, → poly-, + gašt "change, alteration," → -tropic.

1) Math.: Describing a function which has different values for one variable.
2) Thermodynamics: Pertaining to pressure and volume change that maintains specific heat. → polytropic process.

→ poly- + → -tropic.

A change in the → pressure or → volume of a → gas in a → polytropic process.

→ polytropic; → change.

A gas capable of undergoing a → polytropic process.

→ polytropic; → gas.

A number appearing in the equation describing a → polytropic process.

→ polytropic; → index.

A thermodynamic process that obeys the relation: PVⁿ = C, where P is pressure, V is volume, n is any real number, called the → polytropic index, and C is a constant.
If n = 0, then P = C and it is an → isobaric process.
If n = 1, then for an → ideal gas PV = NkT = C and it is an → isothermal process.
If n = γ, → adiabatic index, then for an ideal gas it is an → adiabatic process.

→ polytropic; → process.

1) Chem.: Having more than one → valence.
2) → polyvalent logic.

→ poly-; → valence.

A system of logic with more than two → truth values, as opposed to → classical logic. A polyvalent logic may have a continuous scale of values with → true and → false as limiting → extremes.

→ polyvalent; → logic.

1) Any combination of resources put together to be shared in community, such as memory pool, storage pool.
2) To combine into a common fund, as for a joint enterprise.

1) M.E., O.E. pol, akin to Du. poel, O.H.G. pfuol, Ger. Pfuhl "puddle."
2) Verb from M.Fr. poule (literally "hen") "the receptacle for the stakes played for in certain games with cards, the collective stakes of the players at these games," from M.L. pulla "hen," from L. pullus "young animal," related to L. putus, putillus "small boy," puer "son, boy;" Av. puθra- "son;" O.Pers. puça- "son;" Mod.Pers. pur, pesar "son, boy;" cf. Skt. putrá- "son, child, young of an animal."

Kul "pond, pool, reservoir," variants kulâb, qulé, farqar, related to kulidan "to dig, excavate," Mid.Pers. kwl "pit, sink, cavity."

The act or result of putting resources into a pool or common stock by agreement.

Verbal noun of → pool.

Lacking an expected supply of something specified.

M.E. pov(e)re, from O.Fr. povre, from L. pauper "poor," perhaps a compound of paucus "little" and parare "to get."

Kam "little, few; deficient, wanting; scarce" (Mid.Pers. kam "little, small, few;" O.Pers./Av. kamna- "small, few," related to keh "small, little, slender" (related to kâstan, kâhidan "to decrease, lessen, diminish," from Mid.Pers. kâhitan, kâstan, kâhênitan "to decrease, diminish, lessen;" Av. kasu- "small, little;" Proto-Iranian *kas- "to be small, diminish, lessen") kamdâr, literally "having little possession," from kam + dâr "having, possessor," from dâštan "to have, to possess," Mid.Pers. dâštan; O.Pers./Av. root dar- "to hold, keep back, maintain, keep in mind;" Skt. dhr-, dharma- "law;" Gk. thronos "elevated seat, throne;" L. firmus "firm, stable;" Lith. daryti "to make;" PIE *dher- "to hold, support."

1) Accepted, followed, used, or done by many people.
2) Of, relating to, or coming from most of the people in a country, society, or group (Merriam-Webster.com).

M.E., from M.Fr. populier, from L. popularis "belonging to the people, general, common; devoted to or accepted by the people; democratic," from populus "people," → population.

Mardom-pasand, from mardom, → people, + pasand agent noun from pasandidan "to approve, cherish;" Mid.Pers. passandidan "to like, approve, appreciate;" ultimately from Proto-Ir. *pati-sand- "to appreciate; "from *sand- "to appear, seem (good);" cf. Av. sənd- "to appear; seem (good);" O.Pers. θand- "to seem;" Skt. chand- "to appear, to please;" L. censo "I approve, judge." Mardomâné from mardom + -âné suffix with several significations: similarity, manner, ability, suitability, property, possession, etc., from Mid.Pers. -ânag.

The act of popularizing.

→ popularize; → -tion.

1) To make popular; make attractive to the general public.
2) To make (a scientific or academic subject) accessible to the general public by presenting it in an understandable form (OxfordDictionaries.com).

→ popular; → -ize.

1) To inhabit; live in; be the inhabitants of.
2) To furnish with inhabitants, as by colonization (Dictionary.com).

Infinitive, corresponding to → population.

Statistics: Any finite or infinite set of individuals, items, or data subject to a statistical study. → disk population; → halo population; → population inversion; → Bose-Einstein distribution.

Verbal noun of populate, from M.L. populatus, p.p. of populare "to inhabit," from L. populus "people."

In the IE languages the concepts of "full, many, multitude" and "people, group, herd, flock" are related. In Pers. several variants of por "full, much, many" denote "group, population," as in Lori, Qâyeni bor "group, tribe, herd," Torbat-Heydariyeyi, Qomi borr "heap, bundle, group," Qomi borreh "group, assemblage of people," Pashtu parrak "flock, herd," Urdu para "flock, herd," Lârestâni baila "group, tribe," Tabari balik "herd, flock;" other examples from literary Pers. bâré "herd, flock," parré "a rank or file of soldiers, a circular disposition of troops." Therefore, porineš "population," verbal noun of porinidan "to populate," infinitive of porin "populous," from por "mutitude, many, full" + -in attribution suffix. Por, from Mid.Pers. purr "full;" O.Pers. paru- "much, many;" Av. par- "to fill," parav-, pauru-, pouru- "full, much, many;" PIE base *pelu- "full," from *pel- "to be full;" cf. Skt. puru- "much, abundant;" Gk. polus "many," plethos "great number, multitude;" O.E. full.

A member of a class of relatively young stars, containing a large fraction of → metals, found mainly in the disk of the Galaxy.

→ population; I, Roman number 1; → star.

A member of a population of relatively old stars, containing a small fraction of → metals, found mainly in the → halo of the Galaxy and in → globular clusters.

→ population; II, Roman number 2; → star.

A member of the first generation of stars, formed out of pristine gas, enriched by → primordial nucleosynthesis alone. The material from which these stars formed consisted mostly of hydrogen and helium. Because neutral hydrogen clouds were free of dust, their cooling mechanism was drastically ineffective. As a result, these star forming clouds had a much higher temperature than in the present epoch, and their → Jeans mass was much higher. Therefore, these first generation of stars were principally massive, with a typical mass scale of order of about 100 M_sun. Population III stars started forming about 300 million years after the → Big Bang at → redshifts between 50 and 6, when the Universe had between 1 and 5% of its present age. These stars were probably responsible for the → reionization of the Universe. Given their high mass, they lived only a few million years ending with either a → pair-instability supernova phase or a direct collapse to a → black hole. Population III stars thus initiated the chemical enrichment of the Universe and opened the way to more normal modes of star formation, namely → Population II. Some models predict a bimodal → initial mass function for the first stars, allowing also for solar mass stars. See also → extremely metal-poor star.

→ population; III, Roman number 3; → star.

In physics, specifically statistical mechanics, the state of an atomic or molecular system in which the number of members in an excited state is larger than those in lower energy states. → optical pumping; → inverted population.

→ population; → inversion.