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

The sharp outer boundary of the plasmasphere, at which the plasma density decreases by a factor of 100 or more.

→ plasma + pause "break, cessation, stop," from M.Fr. pause, from L. pausa "a halt, stop, cessation," from Gk. pausis "stopping, ceasing," from pauein "to stop, to cause to cease."

→ plasma + marz "frontier, border, boundary," from Mid.Pers. marz "boundary;" Av. marəza- "border, district," marəz- "to rub, wipe;" Mod.Pers. parmâs "contact, touching" (→ contact), mâl-, mâlidan "to rub;" PIE base *merg- "boundary, border;" cf. L. margo "edge" (Fr. marge "margin"); P.Gmc. *marko; Ger. Mark; E. mark, margin.

In the magnetosphere, a region of relatively cool (low energy) and dense plasma that may be considered an outer extension of the ionosphere with which it is coupled. Like the ionosphere, the plasmasphere tends to co-rotate with the Earth.

→ plasma + → sphere.

Physics: The quasiparticle resulting from the → quantization of → plasma oscillations. Plasmons are collective oscillations of free electrons inside or on surfaces of materials.

From plasm-, from → plasma + → -on.

The research area dealing with the interaction of → plasmons and → photons and the technology of its practical use. Plasmonics represents one of the most active research fields at the interface of → nanotechnology and → optics.

→ plasmon; → -ics.

1a) Capable of being → deformed continuously and permanently without → rupture.
1b) Capable of being molded.
1c) Made or consisting of a plastic.
2) → plastic substance.

From L. plasticus, from Gk. plastikos "that may be molded, pertaining to molding," from plassein "to mold."

Šukâyand, literally "moldable," from šuk, contraction of šuka (Dehxodâ) "a mold in which ingots are cast" + âyand agent noun form of âmadan "to come; to become," → elastic.

Permanent → deformation of a → solid subjected to a → stress.

→ plastic; → deformation.

A substance which remains → deformed after an applied → force ceases to act.

→ plastic; → substance.

The property which enables a material to be → deformed permanently without → rupture during the application of a → force. An → elastic material becomes plastic above its → yield point. See also → elasticity, → ductility.

→ plastic; → -ity.

1) Optics: Any crystalline material whose length is much less than its measured diameter. → half-wave plate.
2) A flat piece of material on which a picture or text has been produced.
3) Any of the large movable segments into which the Earth's lithosphere is divided. → plate tectonics.

M.E., from O.Fr. plate "thin piece of metal," from M.L. plata "plate, piece of metal," perhaps via V.L. *plattus, from Gk. platys " flat, broad."

1) Tiqé, from tiq "blade," related to tiz "sharp," variants tig, tež, tej, tij; Mid.Pers. tigr, têz, têž "sharp," O.Pers. tigra- "pointed," tigra.xauda- "pointed helmet (epithet of Scythians)," Av. tiγra- "pointed," tiγray- "arrow," tiži.arštay- "with the pointed spear," cf. Skt. tikta- "sharp, pungent, bitter," tejas- "sharpness, edge, point or top of a flame;" PIE base *st(e)ig- "to stick; pointed." Cognates in other IE languages: Gk. stizein "to prick, puncture," stigma "mark made by a pointed instrument," L. in-stigare "to goad," O.H.G. stehhan, Ger. stechen "to stab, prick," Du. stecken, O.E. sticca "rod, twig, spoon," E. stick.
2); 3) loanword from Fr., as above.

The celestial coordinates of the center of the field of an astronomical photographic plate.

→ plate; → center.

The scale factor for converting linear measure on a photographic plate to angular measurement on the sky.

→ plate; → scale.

The theory supported by a wide range of evidence in which the Earth's crust is composed of several large, thin, relatively rigid plates that move relative to one another. The interaction of the plates at their boundaries causes seismic and tectonic activity along these boundaries. See also → continental drift.

→ plate; → tectonics.

1) An extensive area with a fairly level surface raised sharply above adjacent land.
2) A period, phase, or state of little or no growth or decline in something. → Spite plateau.

From Fr. plateau, from O.Fr. platel "flat piece of metal, wood, etc.," diminutive of plat "flat surface or thing," → plate.

Taxtâl, from taxt "flat;" Mid.Pers. taxtag "tablet, plank, (chess)board" + -âl, → -al.

1) A small platelike body.
2) One of a variety of forms taken on by → snowflakes.
3) A tiny cell occurring in the blood of vertebrates and involved in clotting of the blood. Formerly called thrombocyte.

→ plate; → -let.

A silvery metallic → chemical element which is tenacious, malleable, and ductile; symbol Pt. → Atomic number 78; → atomic weight 195.08; → melting point 1,772°C; → boiling point 3,827±100°C; → specific gravity 21.45 at 20°C; → valence +2 or +4. It has several short-lived → radioactive isotopes, with the exception of ¹⁹⁰Pt whose → half-life is 6.0 x 10¹¹ years.

From Sp. platina diminutive of plata "silver," from O.Fr. → plate "sheet of metal." The first known reference to platinum can be found in the writing of Italian physician, scholar, and poet Julius Caesar Scaliger (1484-1558). He reported seeing the metal during a visit to Central America in 1557. Aborigines knew of no use for the metal and regarded it as a nuisance in their search for gold and silver. By the end of the 17th century, the Spanish conquistadors started developing the river soil looking for gold and found some gray looking beads together with the gold. They called those little silver beads platina "small silver." They became known as platina del Pinto "granules of silvery material from the Pinto River," a tributary of the San Juan River in the Chocó region of Colombia. The first complete description of platinum was given in 1735 by the the Spanish explorer and naval officer Antonio de Ulloa (1716-1795).

Pelâtin, loanword from Fr.

One of the six metals → platinum (Pt), → iridium (Ir), → osmium (Os), → palladium (Pd), → rhenium (Rh), and → ruthenium (Ru) that are grouped together in the → periodic table. They are relatively hard and resistant to corrosion and are used in jewellery and in some industrial applications. All are resistant to chemical attack.

→ platinum; → group; → element.

The time required for a complete revolution of the Earth's pole on the celestial sphere as the result of → precession. A Platonic year is equal to 25 800 years.

Of or pertaining to Gk. philosopher Plato, from Gk. Platon "broad-shouldered," from platys "broad." → year.

A frequency distribution with negative → kurtosis, which has a smaller "peak" around the mean than the corresponding normal distribution. → leptokurtic.

From Gk. platys "flat", → plate + → kurtosis.

Past-afrâšté, literally "lowly elevated," from past "low; plain" (Mid.Pers. past; proto-Iranian *pasta- "fallen," from *pat- "to fall," cf. Av. pat- "to fall; to fly; to rush," patarəta- "winged;" Mid.Pers. opastan "to fall," patet "falls;" Mod.Pers. oftâdan "to fall," oft "fall;" Skt. patati "he flies, falls," pátra- "wing, feather, leaf;" Gk. piptein "to fall," pterux "wing;" L. penna "feather, wing;" O.E. feðer "feather;" PIE base *pet- "to fly, rush") + afrâšté "raised, elevated, erect," p.p. of afrâštan, → kurtosis.

Pleasing, agreeable, or enjoyable; giving pleasure.

M.E., from O.Fr. plaisant, from plaisir, → pleasure.

1) To act to the pleasure or satisfaction of.
2) To be the pleasure or will of (Dictionary.com).

From M.E. plesen, plaisen, from O.Fr. plaisir "to please, give pleasure to, satisfy," from L. placere "to be acceptable, be liked, be approved," related to placare "to soothe, quiet."

Âzušidan, from prefix â- + zušé, → pleasure, + infinitive suffix -idan.