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

To gather or collect, often in gradual degrees; heap up (Dictionary.com).

From ac-, → ad-, + → cumulate; → amass.

One of the postulates used in the → Bohr model, whereby there are certain steady states of the atom in which electrons can only travel in stable orbits. In spite of their acceleration, the electrons do not radiate electromagnetic waves when they move along stationary orbits.

→ Bohr; → first; → postulate.

One of the three postulates advanced in the → Bohr model which led to the correct prediction of the observed line spectrum of hydrogen atom. See also → Bohr's first postulate, → Bohr's second postulate, → Bohr's third postulate,

→ Bohr; → postulate.

One of the postulates used in the → Bohr model, whereby when an atom is in the steady state an electron travelling in a circular orbit should have → quantized values of the → angular momentum which comply with the condition p = n(h/2π), where p is the angular momentum of the electron, h is → Planck's constant, and n is a positive integer called → quantum number.

→ Bohr; → second; → postulate.

One of the postulates used in the → Bohr model, whereby the atom emits (absorbs) a quantum of electromagnetic energy (→ photon) when the electron passes from an orbit with a greater (lesser) n value to one with a lesser (greater) value. The energy of the quantum is equal to the difference between the energies of the electron on its orbits before and after the transition or "jump": hν = ε₁ - ε₂, where h is the → Planck's constant and ν the frequency of the transition.

→ Bohr; → third; → postulate.

To perform a mathematical process; to reckon; to make an estimate of; evaluate. → compute; → count; → mathematics; → statistics.

Calculate, from L.L. calculare, calculat-, from L. calculus "small stone, pebble" (used in reckoning), dim. of calx, calc- "limestone," from Gk. khalix "small pebble," kakhlex "round pebble,"cf. O.E. hægl, hagol "hale," from W.Gmc. *haglaz, O.H.G. hagal, O.N. hagl, Ger. Hagel "hail", PIE *kaghlo- "pebble, hail." The Pers. cognate is probably the Lori hogela "big stone."

Afmârdan, from prefix af- + stem mar- + infinitive suffix -idan. The Mod.Pers. prefix af- "to, up, upon," occurring in several words (e.g. afzudan, afruxtan, afsar, afsâr, afqân), derives from O.Pers./Av. abiy-/aiwi- "to, upon, against;" cf. Skt. abhi-, Gk. amphi-. The stem mar-, mâr- "count, reckon, measure," which occurs in several Mid./Mod.Pers. terms (e.g. ošmârdan, šomârdan, šomordan "to count, to calculate," âmâr "computation, arithmetic; statistics," âmârdan "to reckon, to calculate," bimar "countless," nahmâr "great, large, big"), is related to the Av. base mar- "to have in mind, remember, recall," hišmar-; cf. Skt. smr-, smarati "to remember, he remembers," L. memor, memoria, Gk. mermera "care," martyr "witness."

If heat flows by conduction from body A to another body B, then a transformation whose only final result is to transfer heat from B to A is impossible. Clausius's postulate is a formulation of the → second law of thermodynamics. It is also equivalent to → Kelvin's postulate.

→ Clausius equation; → postulate.

1) (v.int.) Generally, of liquids, to change into a thickened mass, curdle; congeal.
2) Biology, Medicine: of blood, to form a clot.
3) Physical chemistry: of colloidal particles, to flocculate or cause to flocculate.
4) Astrophysics: of dust grains in the interstellar medium and protoplanetary disks, to grow into larger entities. → dust coagulation.

Mâsidan "to coagulate, clot," originally "of milk, to turn into yogurt," mâst "clotted milk, yogurt;" Gilaki mas, Lori mâs, Kurd. mâzd, mâst, Sangesari must, Baluchi madhagh, mastagh; Mid.Pers. mâs- "to coagulate, become hard;" cf. Skt. mástu- "milk cream," Arm. macum "soar milk," macanim "to clot, congeal."
Rocidan from Lori roc "congealed," rocesse "to congeal, clot."
Laxté bastin lit. "coagulate into (solid) piece," from laxté "piece, part, portion," + bastan "to coagulate, congeal; to bind, shut" (Mid.Pers. bastan/vastan "to bind, shut," Av./O.Pers. band- "to bind, fetter," banda- "band, tie," Skt. bandh- "to bind, tie, fasten," PIE *bhendh- "to bind," cf. Ger. binden, E. bind).

A transparent plate inserted in one of the arms of an interferometer, in particular the → Michelson interferometer, to compensate for a longer → optical path in the other arm. Its function is to ensure that the beams transverse the same total thickness of glass in both arms of the interferometer. This is not essential for producing → interference fringes in monochromatic light. The compensator plate is of the same glass and the same thickness as the → beam splitter plate.

→ compensator; → plate.

1) To look at with continued attention.
2) To think about intently and at length.

From L. contemplatus, from contemplari "to gaze attentively, observe," from → com- + templum "space marked out for observation of auguries."

Darnegaristan "contemplate, think deeply," from prefix dar- "→ in-, into," + negaristan "to look," → theory.

A large glass plate placed at the entrance of a Schmidt telescope to correct for spherical aberration over the large field of view.

→ correct; → plate.

1) To place in or bring into causal or mutual relation.
2) To have a mutual or reciprocal relation.

From co-, → com-, + relate, → relation

Hambâzânidan , from ham-→ com- + bâzânidan→ relate.

To heap up; → amass; → accumulate.

From L. cumulatus "heaped, increased, augmented," p.p. of cumulare "to heap," from cumulus "mound, heap," from PIE *ku-m-olo-, from *keue- "to swell;" cf. Skt. śavi "to swell;" svayati "swells up, is strong;" Av. su-, sauu- "to bulge, swell up, increase;" Proto-Ir. *sauH- "to bulge, swell up, increase" (Cheung 2007, Pers. sud "gain, profit"); Gk. kuein "to swell;" Lith. saunas.

Kumidan, from kum, kumé "heap;" Hamedâni kumelé, kumelân "heap, pile, mound," kumé kardan "to accumulate;" Kurd. kom "pile, group," komel "society, organization," related to Pers. kud "heap" (Mid.Pers. kôt), Gilaki kô-pâ "warehouse, barn," kô-gâh "gathering site." In the Gilan province there are several localities with protruding positions that bear names with an initial kom- (such as komâcâl, komâdol, kumélé, komsâr, etc.); probably related to L. cumul-, as above; if confirmed, interestingly it relates to the PIE form *keue- in contrast with Proto-Ir. *sauH-, as above.

A quadrilateral in which all four vertices lie on the circumference of a circle.

→ cyclic; → quadrilateral.

To remove or reduce the population of, as by destruction or expulsion (Dictionary.com).

→ de-; → populate.

1) (v.tr.) To make wider or larger; cause to expand.
2) (v.intr.) To spread out; expand.

M.E. dilaten, from O.Fr. dilater, from L. dilatare "make wider, enlarge," from → dis- "apart" + latus "wide," → latitude.

Farâxândan, farâxidan, infinitive from farâx "broad, wide, spacious;" Mid.Pers. frâxv, fraxv "broad, wide," frâxvitan, frâxvênitan "to spread."

A measure of the extent to which mass has been shifted from the polar regions of a (spinning) body toward its equator (Ellis et al., 2007, Planetary Ring Systems, Springer).

→ dynamic; → oblateness.

A triangle having three equal sides.

→ equi-, → lateral, → triangle.

Sé-pahlu-barâbar, from sé, → three, pahlu, → side, barâbar, → equal.

Math.: To estimate the value of a result outside the range of a series of known values.

From → extra- + (inter)polate, → interpolate.

From borun, → extra- + yâftan, yâbidan "to find, discover; to obtain, acquire;" Mid.Pers. ayâftan, ayâpênitan "to reach, attain;" Manichean Mid.Pers. 'y'b "to attain;" Parthian, Sogdian (+ *pati-) pty'b "to reach, obtain;" Av. ap- "to reach, overtake," apayeiti "achieved, reached;" Skt. âp- "to reach, gain," âpnoti "reaches, gains;" Gk. hapto, haptomai "to touch, cling to, adhere to;" L. apiscor "touch, reach;" PIE base *ap- "to take, reach."

1) To tell invented stories; create fables or stories filled with fantasy.
2) To relate an event as a fable.

From L. fabulatus perfect passive participle of fabulor, from fabula, → fable.

Afsâne-bâftan "to forge fables, stories," from afsâné, → fable, + bâftan "to weave, twist, plait," → texture.