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

The return of radiation after striking a surface, without change in wavelength. If the surface is smooth, reflection is regular, otherwise it is diffuse. → diffuse reflection; → specular reflection.

Verbal noun of → reflect.

The ratio given by the → amplitude (or energy) of a reflected wave divided by the amplitude (or energy) of the incident wave.

→ reflection; → coefficient.

The ratio of total flux that is reflected from a surface to the incident flux. Also called reflectance, reflectivity.

→ reflection; → factor.

A type of nebula that is visible from its reflection of starlight. Bright stars near reflection nebulae emit light into the region that is reflected by the large amount of dust there. The size of the dust grains causes blue light to be reflected more efficiently than red light, so these reflection nebulae frequently appear blue in color.

→ reflection; → nebula.

That reflects; reflecting. Of or pertaining to reflection.

From → reflect + -ive a suffix of adjectives and nouns of adjectival origin.

Bâztâbi adj. of bâztâb, → reflection.

Same as → reflectance; → reflection factor.

From → reflective + → -ity.

1) A → reflecting telescope.
2) A type of conducting surface or material used to → reflect radiant energy.

From reflect, → reflection, + → -or.

1) (n.) The improvement, amendment, or reorganization of something that is considered to be wrong, ineffective, or unsatisfactory; e.g. calendar reform.
2) (v.tr.) To change and improve by correction of faults, alteration, substitution, abolition, etc.

From M.E. reformen, from M.Fr. reformer, from O.Fr., from L. reformare "to form again, change, alter," from → re- "again" + formare "to form," from forma "form, mold, shape, case," origin unknown.

1) Bâzdisi, from bâz- "again," → re-, + dis, disé "form, appearance," (variants -diz, -diš (tandis "body form, like a body; effigy; statute;" mâhdis "moon-like;" šabdiz "night color; a horse of dark rusty color;" andiš- "to think, contemplate"); Mid.Pers. dêsag "form, appearance," dêsidan "to form, build;" Av. daēs- "to show," daēsa- "sign, omen;" cf. Skt. deś- "to show, point out;" PIE *deik- "to show" (cf. Gk. deiknumi "to show," dike "manner, custom;" L. dicere "to utter, say;" O.H.G. zeigon, Ger. zeigen "to show;" O.E. teon "to accuse," tæcan "to teach") + -i noun suffix.
2) Bâzdisidan infinitive from bâzdisi, as above.

To alter the course of a wave of light, sound, etc. when the wave crosses the boundary between this medium and another through which it travels at a different speed.

From L. refractus, p.p. of refringere, → refraction.

Verb of šekast, → refraction.

A → light ray that undergoes a change of velocity and direction, as a result of interaction with the material medium in which it travels.

→ reflect; → ray.

1) The action or result of the verb → refract.
2) Participial adjective of → refract.

From → refract + → -ing.

A prism that is used as a dispersing element in a spectrograph.

→ refracting; → prism.

A telescope in which an image is formed by the refraction of light through a lens or lens system.

→ refracting; → telescope.

1) Optics: The change of direction which a beam of light undergoes as it enters a medium of different → refractive index.
2) Acoustics: The change in direction in sound waves on reaching the boundary between two media.
3) Seismology: The bending of a seismic wave as it enters a material of different density.

From L.L. refractionem (nominative refractio) "a breaking up," from L. refractus, p.p. of refringere "to break up," from re- "back" + combining form of frangere "to break," from PIE base *bhreg- "to break" (cf. Goth. brikan, O.E. brecan "to break;" Lith. brasketi "crash, crack").

Šekast, past stem of šekastan "to break, split;" Mid.Pers. škastan "to break;" Av. scind-, scand "to beak, cleave;" Proto-Iranian *skand- "to break, cleave;" PIE sken- "to cut off."

Of any optical medium, the ratio of the → speed of light in vacuum (c) to that in the medium (v): n = c/v. The refractive index for vacuum, by definition, is 1. The refractive index of air is 1.00029 at standard temperature (25 °C) and pressure (1 atm). The refractive index of a medium depends on the wavelength of refracted wave. With light waves, n increases as the wavelength decreases. → Snell's law can be used to derive n. Same as → index of refraction.

Refractive, pertaining to → refraction; → index.

Same as → refracting telescope.

Agent noun of refract, → refraction.

A substance that has a high → melting point. It is therefore resistant to treatment and not easily melted or worked. The opposite of → volatile.

From refract, → refraction + adj. suffix -ory.

Sarkeš "refractory, disobedient, rebellious, stubborn," literally "withdrw, remove head," from sar "head" (variants soru, sorun "horn," karnâ "a trumpet-like wind instrument," variant sornâ "a wind instrument;" Mid.Pers. sar "head," sru "horn;" Av. sarah- "head," srū- "horn, nail;" cf. Skt. śiras- "head, chief;" Gk. kara "head," karena "head, top," keras "horn;" L. cornu "horn," cerebrum "brain;" P.Gmc. *khurnaz (Ger. Horn, Du. horen; cognate with E. horn, as above, from PIE *ker- "head, horn;" O.E. horn "horn of an animal," also "wind instrument;" E. horn); PIE base *ker- "head, horn, top, summit") + keš present stem of kešidan, kašidan "to draw; withdraw, remove" (dialectal Yaqnavi xaš "to draw," Qomi xaš "streak, stria, mark," Lori kerr "line;" Av. karš- "to draw; to plow," karša- "furrow;" Proto-Iranian *kerš-/*xrah- "to draw, plow;" cf. Skt. kars-, kársati "to pull, drag, plow;" Gk. pelo, pelomai "to move, to bustle;" PIE base k^wels- "to plow").
Dirgodâz, literally "melting slowly, with delay," from dir "slowly, tardily; late" (Mid.Pers. dêr, variants dagr, drâz "long;" (Mod.Pers. derâz "long," variant Laki, Kurdi derež); O.Pers. darga- "long;" Av. darəga-, darəγa- "long," drājištəm "longest;" cf. Skt. dirghá- "long (in space and time);" L. longus "long;" Gk. dolikhos "elongated;" O.H.G., Ger. lang; Goth. laggs "long;" PIE base *dlonghos- "long") + godâz-, godâxtan "to melt" (Mid.Pers. vitâxtan, vitâcitan "to melt," from Av. vi-taxti- "flowing away, melting," from vi- "apart, away from, out" (O.Pers. viy- "apart, away;" cf. Skt. vi- "apart, asunder, away, out;" L. vitare "to avoid, turn aside") + tak- "to run, to flow," taciāp- "flowing water," tacinti (3pl.pers.act.) "to flow," tacar- "course," tacan "current, streaming;" Mod.Pers. tâz-, tâxtan "to run; to hasten; to assault," tâzi "swift (greyhound)," tak "running, rush;" Mid.Pers. tâz-, tâxtan "to flow, to cause to walk," tc- "to flow, to walk," tag "running, attack," tâzig "swift, fast;" Khotanese ttajs- "to flow, to walk;" cf. Skt. tak- "to rush, to hurry," takti "runs;" O.Ir. tech- "to flow;" Lith. teketi "to walk, to flow;" O.C.S. tešti "to walk, to hurry;" Tokharian B cake "river;" PIE base *tek^w- "to run; to flow").

An act or instance of refusing.

→ refuse; → -al.

Nežan, from ne- "down, below," → ni-, + žan variant of zan present stem of zadan "to hit, strike," variants Zazaki jinen-, Gazi žen-/žent "to beat, hit," Baluchi jat/jan- "to strike, hit," Awromani žanây/-žan- "to shut (the door)," Pashto -žan "to chop, mince," → beat.

1) To decline to accept (something offered).
2) To decline to give (Dictionary.com).
See also: → refute, → reject, → repulse, → recoil.

M.E. refusen, from M.Fr. refuser, from L. refusus, p.pa. of refundere "to give back," from → re- "back" + fundere "to pour."

Verb from → refusal.

The quality of being → refutable.

→ refutable; → -ity.