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

An electromagnetic spectrum in which emitted or absorbed radiation is present continuously over all wavelengths in a given range.

→ continuous; → spectrum.

Binâb, → spectrum; peyvasté→ continuous.

A variable which has changes continuously, in contrast to → discrete variables.

→ continuous; → variable.

A → quantum walk taking place entirely in the position space. Continuous-time quantum walk was introduced by E. Farhi & S. Gutmann (1998, Phys. Rev. A 58, 915).

→ continuous; → time; → quantum; → walk.

A continuous extent or succession, which has no discrete parts, as the continuum of real numbers as opposed to the sequence of discrete integers. → continuum emission.

From L. neut. of continuus, → continuous

Peyvastâr, from peyvast past tense stem of peyvastan "to connect, join," Mid.Pers. paywastan, from *pati-basta-, from suffix pati- (Mid.Pers. pât-, from O.Pers. paity "agaist, back, opposite to, toward, face to face, in front of," Av. paiti, akin to Skt. práti "toward, against, again, back, in return, opposite," Pali pati-, Gk. proti, pros "face to face with, toward, in addition to, near;" PIE *proti) + basta- "tied, 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), cf. Skt. prati-bandh- "to tie." + -âr suffix forming verbal noun.

A continuous radiation produced by three processes: radiative recombination due to transition between electron free-free states, two-photon decays of metastable levels, and thermal bremsstrahlung.

→ continuum; → emission.

The transfer of photon momentum to free electrons. The acceleration by → continuum emission can be given by: a_c = (σ/m)(L_*/4πR²c), where σ is the → Thomson scattering  → cross section, m is the mass per free electron, L_* is → stellar luminosity, R_* is radius, and c the → speed of light. The ratio of a_c to the → surface gravity is ≅ 2 × 10^-5L_*/M_*, with M_* and L_* in solar units. The atmosphere is is stable if a_c very smaller than g_grav. If L_* is above the → Eddington limit, the radiation pressure in the continuum leads to very heavy → mass loss and thus to expanding envelopes (K.S. de Boer & W. Seggewiss, 2008, Stars and Stellar Evolution, EDP Sciences).

→ continuum; → drive; → wind.

The outline of a figure or body; the edge or line that defines or bounds a shape or object.

From Fr. contour "circumference, outline," from Italian contorno, from M.L. contornare "to go around," from L. → com- intens. prefix + tornare "to turn on a lathe," from tornus "lathe."

Parband, from par- "around" (Mid.Pers. pêrâ, O.Pers. pariy "around, about," Av. pairi "around, over," Skt. pari, cf. Gk. peri "around, about, beyond," L. per "through," PIE *per- "through, across, beyond") + band "belt, gridle, anything by which bodies are joined; tie, band," from bastan "to bind, shut," (Mid.Pers. bastan/vastan,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 line joining points of equal elevation or on a surface or points of equal intensity in a map.

→ contour; → line.

A map showing the flux intensity variations over an extended object made up of → contour lines.

→ contour; → map.

A prefix meaning "against; contrary; opposing."

From L. contra "against," passed (via O.Fr.) into E. as → counter-.

1) To become smaller, shorter, tighter, as a metal when cooled.
2) To reduce to smaller size by or as if by squeezing or forcing together, e.g. contract a muscle.
→ contraction, → gravitational contraction, → Kelvin-Helmholtz contraction, → length contraction, → Lorentz contraction, → vena contracta.

From M.E., from O.F., from L. contractus, p.p. of contrahere "to draw together," from → com- "together" + trahere "to draw."

Terengidan, variant taranjidan [Dehxodâ] "to contract, become rough and hard, to be squeezed, compressed," Borujerdi terengessa "cramped, tightly dressed," Malâyeri terengidan "to be tightly dressed, cramped in a garment," related to tarang "horse girth, a strap for fastening a load," Proto-Iranian *trng- "to pull tight, squeeze, compress;" PIE base *strenk- "to pull tight, twist; tight, narrow" (cf. L. stringere "to bind or draw tight;" Gk. strangein "to twist;" Lith. stregti "to congeal;" O.E. streccian "to stretch," streng "string;" Ger. stramm, Du. stram "stiff").

An act or instance of contracting; the quality or state of being contracted.
→ gravitational contraction, → Kelvin-Helmholtz contraction, → length contraction, → Lorentz contraction.

Verbal noun of → contract.

1) The act of contradicting; assertion of the contrary or opposite.
2) Logic: A statement that is false under all circumstances.

M.E., from O.Fr. contradiction or directly from L. contradictionem "objection, counterargument," from contradicere, from contra dicere "to speak against," from → contra- "against" + dicere "to speak," akin to Pers. dis, → form.

Pâdguyi, literally "speaking against," from pâd, → counter-, + guyi, from goftan, → logic.

Asserting the contrary or opposite; contradicting; inconsistent; logically opposite (Dictionary.com).

Adjective from → contradiction.

1) Opposite in nature or character; diametrically or mutually opposed.
2) Opposite in direction or position (Dictionary.com).

From Anglo-French contrarie, O.Fr. contrarie, and directly from L. contrarius "opposite, opposed; contrary, reverse," from contra "against"

Pârun, → opposite.

In an → image, the degree of distinction between areas with different → brightness levels; in other words, the → ratio of the brightness between light and → dark areas.

From Fr. contraster, from It. contrastare "stand out against," from V.L. *contrastare "to withstand," from L. → contra- "against" + stare "to stand," (cf. Pers. istâdan "to stand," O.Pers./Av. sta- "to stand, stand still; set," Skt. sthâ- "to stand," Gk. histemi "put, place, weigh," PIE base *sta- "to stand").

Pâdsâni, from pâd- "agianst," → contra- + sân "manner, semblance," variant sun, Mid.Pers. sân "manner, kind," Sogdian šôné "career" + -i noun suffix.

A tensor whose components are distinguished by → superscript indices.

→ contra-; + variant; → variance; → tensor.

1) To give or supply (help, money, etc.) for a common purpose.
2) To provide (ideas, suggestions, work, etc.) for a common goal, such as an article, a book.

From L. contributus, p.p. of contribuere "to bring together, unite, collect," from → com- + tribuere "to pay, assign, allot," from tribus "tribe."

Hambâžidan, from ham- "together," → com-, + bâž "tribute, toll, impost," → distribute.

1) The act of contributing.
2) Something contributed.

Verbal noun of → contribute.

In general, mass motions within a → fluid resulting in transport and mixing of the properties of that fluid when the temperature gradient exceeds some critical value. Convection, along with → conduction and → radiation, is a principal means of → energy transfer. → Schwarzschild's criterion.

From L. convectionem "the act of carrying," from p.p. stem of convehere "to carry together," from → com- "together" + vehere "to carry," cf. Skt. vah- "to carry, lead," vahitra "vehicle," Av. vazaiti "to lead," Mid.Pers. waz-, wazidan "to carry away," Gk. oxos "chariot;" PIE base *wegh- "to go, carry, drive"

Hambaz, from ham- "together" + baz "to carry, move," → evection.
Hambord, from ham- "together," → com- + bord, from bordan "to carry," Mid.Pers. burdan, O.Pers./Av. bar- "to bear, carry," barəθre "to bear (infinitive)," Skt. bharati "he carries," Gk. pherein, L. fero "to carry," PIE base *bher- "to carry."