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

Mechanics: For a rotating rigid body not subject to external torque, the closed curve described on the → inertia ellipsoid by the intersection with this ellipsoid of an axis parallel to the angular velocity vector and through the center.
Astro.: The path described by the North pole of the Earth in a reference frame attached to the Earth. The rotation axis of our planet is not fixed with respect to the Earth's crust. It describes a motion within a square with an amplitude reaching 20 m.

Polhode, from Fr. polhodie, coined by Louis Poinsot (1777-1859), a French mathematician and physicist, the inventor of geometrical mechanics, from → pole + Gk. hodos "way."

Qotbrâh, from gotb, → pole, + râh "way, path" (from Mid.Pers. râh, râs "way, street," also rah, ras "chariot;" from Proto-Iranian *rāθa-; cf. Av. raθa- "chariot;" Skt. rátha- "car, chariot," rathyā- "road;" L. rota "wheel," rotare "to revolve, roll;" Lith. ratas "wheel;" O.H.G. rad; Ger. Rad; Du. rad; O.Ir. roth; PIE *roto- "to run, to turn, to roll").

1) A definite course of action adopted for the sake of expediency, facility, etc.
2) A course of action adopted and pursued by a government, ruler, political party, etc. (Dictionary.com).

M.E. policie "government, civil administration," from O.Fr. policie "political organization, civil administration," from L.L. politia "the state, civil administration," from Gk. politeia "state, administration, government, citizenship," from polites "citizen," from polis "city, state."

Kârâh, contraction of kâr râh, or râh-e kâr literally "way of doing, ~ ~ action," from râh, → way, + kâr "doing, action, → work."

A person responsible for making policy, especially in government (Dictionary.com).

→ policy; → make; → -er.

To make smooth and glossy by rubbing with something.

M.E. polishen, from O.Fr. poliss-, pr.p. stem of polir "to polish," from L. polire "to polish, make smooth," of unknown origin.

Nasu kardan (Dehxodâ) "to polish, smooth, brighten," from nasu "smooth, bright" (mirror, sword), Mid.Pers. Manichean Parthian nswg "tender," from Proto-Iranian *ni-sau-, from prefix ni- "down," → ni- (PIE), + *sau- "to rub;" cf. Mod.Pers. sâbidan, variants sâyidan, pasâvidan "to touch, to rub;" Khotanese sauy- "to rub;" Sogdian ps'w- "to touch."

A stage in the process of mirror making after grinding that puts a highly finished, smooth and apparently amorphous surface on a mirror. → figuring; → grinding.

Verbal noun of → polish.

1) Shrewd or prudent in practical matters; tactful; diplomatic.
2) Contrived in a shrewd and practical way.
3) Political (Dictionary.com).

M.E. politik, from M.Fr. politique "political," from L. politicus "of citizens or the state, civil, civic," from Gk. politikos "of citizens, pertaining to the state and its administrators," from polites "citizen," from polis "city."

Kârâhi, adj. of kârâh, → policy.

Of, pertaining to, or concerned with → politics.

→ politic; → -al.

A person who studies the structure and theory of government and seeks practical and theoretical solutions to political problems.

→ political; → scientist.

Kârâhikdân, literally "politics scientist," from kârâhik, → politics, + dân "knower," present stem of dânestan, → science.

1) A person who is active in party politics.
2) A person who holds a political office.
3) A person skilled in political government or administration; statesman or stateswoman (Dictionary.com).

From politic + -ian an agent noun suffix.

Kârâhigar, from kârâhi-, contraction of kârâhik, → politics, because of the k-g succession, + -gar, → -or.

1) The science or art of → political  → government.
2) The practice or profession of conducting political affairs.
3) Political → principles or → opinions (Dictionary.com).

From adj. → politic modeled on Aristotle's ta politika "affairs of state," the name of his book on governing and governments; → -ics.

Kârâhik, from kârâh, → policy, + -ik, → -ics.

Powdery grains that contain the male reproductive cells of most plants (Dictionary.com).

From L. pollen "mill dust; fine flour," related to polenta "peeled barley," and probably to Gk. poltos "pap, porridge."

Gardé, from gard "powder, dust."

The introduction of harmful substances or light into the natural environment as a consequence of human activities. → light pollution.
The act of polluting or the state of being polluted.

M.E., from O.Fr., from L.L. pollutionem "defilement," from L. polluere "to soil, defile," from pol-, variant of por- "forth, forward, before" + -luere "smear," related to lutum "mud," and to lues "filth; plague, pestilence;;" cf. Gk. luma "filth, dirt, disgrace;" O.Ir. loth "mud, dirt;" Lith. lutynas "pool, puddle;" Pers. âludan, as below.

Âludegi, from âludan, âlây-"to pollute, soil, stain;" Mid.Pers. âlutan; from prefixed Proto-Iranian *ā-rūta-, from rav- "to stain, soil;" Mid.Pers. Manichean Parthian rwd "rascal;" PIE base *leu- "dirty; to soil;" cf. L. lues, as above.

The brightest star in the constellation → Gemini despite its designation as β. Also known as HR 2990 and HD 62509. Pollux lies about 4 degrees apart from the blue star → Castor with which it has no physical connection. Pollux is an orange-red star with a → visual magnitude 1.14 (B - V = +1.00) located about 34 → light-years away. It is a → giant star of → spectral type K0 III, with a mass of 2 Msun, a radius of about 10Rsun, a luminosity of 43 Lsun, and an → effective temperature of 4666 K. Pollux has a large planet, → Pollux b, with a mass of at least 2.3 times the mass of Jupiter.

Pollux, Gk. Polydeucus is one of the "Heavenly Twins," brother to → Castor, sons of Leda and Zeus.

Pollux, loan from L., as above. It has a too long Ar. name: Al-Ra's-at-Tau'am-al-Mo'akhkhar (الرأس‌التوأم‌المؤخر) "the head of the posterior twin," translating the Gk. mythological figure.

An → extrasolar planet orbiting the bright star → Pollux (β Gem). It lies approximately 34 → light-years away in the constellation → Gemini. Called also → Thestias, it has a mass of at least 2.30 → Jupiter mass, and orbits Pollux at a distance of about 1.64 → astronomical units once every 590 days.

→ Pollux.

1) In → protoplanetary disk models, the magnetic field whose large-scale lines of force depart away from the → accretion disk, in the direction of the rotation axis.
2) In a → tokamak, the magnetic field produced by a current flowing in the → plasma vertically to the toroid plane. → toroidal magnetic field.

→ pole; → -oid; → magnetic field.

A radioactive chemical element; symbol Po. Atomic number 84; mass number of most stable isotope 209; melting point 254°C; boiling point 962°C.

The name derives from Poland, the native country of Marie Sklodowska Curie. It was discovered by Pierre and Marie Curie in 1898, from its radioactivity.

A prefix denoting "much, many."

From Gk. poly-, combining form of polus "much," cognate with L. plus, Pers. bol-, as below; from PIE base *pel- "to be full."

Bol- "much; very; many," as in examples bolkâmé "desirous" (literally "with much desire"), bolhavas, variant porhavas "very desirous, libidinous" (literally "with much lust"); variant of por "full, much, very," Mid.Pers. purr "full;" O.Pers. paru- "much, many;" Av. parav-, pauru-, pouru- "full, much, many," from par- "to fill;" PIE base *pelu- "full," from *pel- "to be full;" cf. Skt. puru- "much, abundant;" Gk. plethos "great number, multitude;" O.E. full.
Cand-, from cand "how many, how much; so many; several; some; much;" Mid.Pers. cand "how many?, so many; much; some;" O.Pers. yāvā "as long as;" Av. yauuant- [adj.] "how great?, how much?, how many?," yauuat [adv.] "as much as, as far as;" cf. Skt. yāvant- "how big, how much;" Gk. heos "as long as, until."

Having or exhibiting a variety of colors.

→ poly-; → chromatic.

1) Chemistry: A family of → organic molecules composed of carbon and hydrogen atoms (→ hydrocarbons) in which → carbon atoms appear in multiple loops (polycyclic) with strong chemical → bonds that exist between them (aromatic). PAHs are formed during the incomplete burning of coal, oil and gas, garbage, or other organic substances like tobacco or charbroiled meat. As a pollutant, they are of concern because some compounds (benzo(a)pyrene) have been identified as tending to cause cancer.
2) Astro.: Strong → infrared emission features at 3.3, 6.2, 7.7, 8.6, and 11.2 microns, which are attributed to PAH molecules in the form of → dust grains with radii smaller than 10 Å. PAHs are common toward various sources characterized by a strong → ultraviolet radiation field (such as → active galaxies, → reflexion nebulae, → planetary nebulae, → H II regions). In particular, they trace the presence of → massive stars. The PAH features are thought to result from the fluorescent emission process of PAH molecules and ions excited by ultraviolet radiation of nearby stars. PAHs are likely produced by → photoevaporation of → very small grains.

→ poly-; → cyclic; → aromatic; → hydrocarbon.

A kind of → deism according to which multiple deities created the Universe, but do not interact with the physical world. → polytheism.

→ poly-; → deism.