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

1) The act, process, or result of developing. The state of being developed.
2a) Math.: The act or process of → expanding an expression into another of equivalent value or meaning.
2b) The equivalent expression into which another has been developed.

From → develop + -ment suffix forming nouns from verbs.

Govâleš, from govâl, stem of govâlidan, → develop, + -eš verbal noun suffix, → -tion.

1) (v. intr.) To turn aside, as from a way, course, etc. By extension, to depart from a course of action or acceptable norm.
2) (v.tr.) To cause to turn aside. → deviation, → standard deviation.

From L.L. deviatus "turned from the straight road," p.p. of deviare, from → de- + via "road," + -ate.

1) Kažraftan, from kaž "crooked, bent, being aside" (cf. Skt. kubja- "hump-backed, crooked," Pali kujja- "bent," L. gibbus "hump, hunch," Lith. kupra "hump") + raftan "to go, walk, proceed" (present tense stem row-, Mid.Pers. raftan, raw-, Proto-Iranian *rab/f- "to go; to attack").
2) Kažrâh kardan, from kaž, as above, + râh "way, path" (Mid.Pers. râh, râs "way, street," from *rāθa-, cf. Av. ratha- "chariot," akin to Skt. rathah "car, chariot," L. rota "wheel," rotare "revolve, roll," Lith. ratas "wheel," O.H.G. rad, Ger. Rad, Du. rad, O.Ir. roth; PIE *roto- "to run, to turn, to roll") + kardan "to do, to make," Mid.Pers. kardan, O.Pers./Av. kar- "to do, make, build," Av. kərənaoiti "makes," cf. Skt. kr- "to do, to make," krnoti "makes," karma "act, deed;" PIE base k^wer- "to do, to make."

The act of deviating; departure from a standard or norm.
Statistics: The difference between a datum and some reference value, typically the mean of the data. → standard deviation.

Verbal noun form of → deviate.

Something, thought out, invented, or adapted, for a special purpose.
Assembly of parts or pieces in one body to perform a work, observe a phenomenon, or for measuring.

From O.Fr. devis "division, separation, disposition, wish," from L. divisus, p.p. of dividere "to divide," → divide.

Dastgâh "means, implement, apparatus," originally "wealth, splendour," from dast "strength, superiority," originally "hand" (Mid.Pers. dast, O.Pers. dasta-, Av. zasta-, cf. Skt. hásta-, Gk. kheir, L. praesto "at hand," Arm. jern "hand," Lith. pa-žastis "arm-pit;" PIE *ghes-to-) + gâh "place, time," O.Pers. gāθu-, Av. gātav-, gātu- "place, throne, spot" (Skt. gâtu- "going, motion; free space for moving; place of abode," PIE *gwem- "to go, come").

An evil spirit; demon. → dust devil.

M.E. devel, from O.E. deofol, from L.L. diabolus, from Gk. diabolos, literally, "slanderer," from diaballein "to throw across, slander," from dia- "across, through" + ballein to "throw."

Div "devil, demon" (Mid.Pers. dêw; O.Pers. daiva- "evil god, demon;" Av. daēva- "evil spirit, false god;" Skt. deva-; Gk. Zeus "supreme god;" L. deus "god;" PIE base *deiwos "god," from *dei- "to gleam, to shine").

To apply or dedicate (oneself, time, money, etc) to some pursuit, cause, etc. (Dictionary.com).

From L. devotus, p.p. of devovere "dedicate by a vow, sacrifice oneself, promise solemnly," from → de- "down, away" + vovere "to vow," from votum "a promise to a god, solemn pledge, dedication; that which is promised; a wish, desire, prayer," from PIE root *wegwh- "to speak solemnly, vow, preach;" cf. Skt. vaghat- "one who offers a sacrifice;" Gk. eukhe "vow, wish."

Âdaxtan, on the model of pardâxtan (among several meanings) "to devote, consecrate, to be busily and attentively engaged; to attempt, care about; to employ" (Steingass), with prefix â- and stem âxt, âz- (→ theoretician).

1) Profound dedication; consecration.
2) Earnest attachment to a cause, person, etc. (Dictionary.com).

Verbal noun of → devote.

1) Water condensed onto grass and other objects near the ground, the temperatures of which have fallen below the dewpoint of the surface air due to radiational cooling during the night, but are still above freezing.
2) Moisture in small drops on a surface.

O.E. deaw, from P.Gmc. *dawwaz, O.H.G. tow, Gk. thein, "to run," thoos "quick," PIE base *dheu- "to run, flow" (cf. Pers. dav-, davidan "to run," Skt. dhav- "to run, flow," dhavati "flows, runs").

Šabnam, from šab→ night + nam "moisture; dew; wet," Mid.Pers. namb, nam, Av. napta- "moist," nabas-câ "cloud," nabah- "sky," Skt. nábhas- "moisture, cloud, mist, sky," Gk. nephos "cloud," L. nebula "mist," PIE base *nebhos- "moisture, cloud, mist."

A hollow tube that extends out in front of the objective lens (refractors) or corrector lens (Schmidt-Cassegrains). It shields the exposed optics from wide exposure to the cool ambient air, slowing heat loss and preventing dew formation. Reflector telescopes do not need dew caps because the main mirror rests at the bottom of the tube, which acts as a dew shield.

→ dew + cap, from O.E. cæppe "hood, head-covering," from L.L. cappa "a cape, hooded cloak."

Kolâhak, from kolâh "cap," see below, + similarity suffix -ak. Kolâh "cap," cf. L. celare "to hide, conceal," occulere "to dissimulate," Gk. kalyptein "to cover," kalia "hut, nest," Skt. cala "hut, house," Goth. hilms "helmet," huljan "cover over," hulistr "covering," E. hull "seed covering," from O.E. hulu, from O.H.G. hulla, hulsa, O.E. hol "cave;" PIE base *kel- "conceal." Šabnam→ dew.

The temperature to which a given air parcel must be cooled at constant pressure and constant water vapor content in order for saturation to occur.

→ dew; → point.

Insulated bottle containing a cryogenic fluid. The electronic detectors operated at very low temperature are mounted inside a dewar.

Named after its inventor Sir James Dewar (1842-1923), Scottish chemist and physicist.

A rainbow formed in the small drops often found on grass in early morning. While the name implies that those drops are dew, that is probably rarely the case. Rather, the drops are usually the result of guttation (the water exuded from leaves as a result of root pressure) rather than dew.

→ dew; → bow.

A conventional notation for decimal exponent, which converts the number after it into its common antilogarithm; for example, dex (2.35) = 10^2.35.

From decimal + exponent.

A combining form meaning "right" and "turning clockwise," used in the formation of compound words, e.g. → dextrorotatory, dextrocardia, dextrocular, etc. The variant dextr- occurs before vowels. Compare → levo-.

From L. dextr-, from dexter "right, right-hand;" cf. Gk. dexios "right," dexiteros "located on the right side;" Av. dašina- "right; south" ( Mid.Pers. dašn "right hand; " Ossetic dæsni "skillful, dexterous"); Skt. dáksina- "right; southern;" Goth. taihswo "right hand;" O.Ir. dess "on the right hand, southern;" PIE base *deks- "right;" + epenthetic vowel -o-; see also → south.

Râst- from râst, → right.

The clockwise rotation of the → plane of polarization of light (as viewed by an observer looking straight in the incoming light) by certain substances. See also → levorotation.

→ dextro-; → rotation.

Relating to an → optically active substance that causes → dextrorotation.

Adj. related to → dextrorotation.

A prefix meaning "two; twice; double." → dimer, → diode, → dipole, → diproton.

L. di, from Gk., → two.

To identify the nature of (an illness or other problem) by examination of the symptoms (OxfordDictionaries.com).

→ diagnosis.

1) The process of determining by examination the nature and circumstances of a diseased condition.
2) The decision reached from such an examination.
3) Scientific determination; a description that classifies a group or taxon precisely; a determining or analysis of the cause or nature of a problem or situation (Dictionary.com).

L., from Gk. diagnosis "a discerning, distinguishing," from stem of diagignoskein "discern, distinguish," literally "to know thoroughly," from dia- "through" + gignoskein "to learn," cognate with Pers. šenâs-, šenâxtan "to know, to be acquinted" and dânestan "to know," as below, ultimately from PIE root *gno- "to know."

Parnâs, from par- "through," + nâs "to know," as in Zazaki nâs- "to know," Kurd. nâs-, nâsîn "to know," related to Pers. šenâs- "to know," related to šenâxtan, → knowledge and dânestan, → science.

1a) Of, relating to, or used in → diagnosis.
1b) Serving to identify or characterize; being a precise indication.
2a) Diagnosis.
2b) A symptom or characteristic of value in diagnosis.
2c) A message output by a computer diagnosing an error in a computer program, computer system, or component device; a program or subroutine that produces such messages (Dictionary.com).

From Gk. diagnostikos "able to distinguish," → diagnosis.

→ diagnosis.