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

1) The evolution of the properties of a physical system which has been disturbed and which regains its equilibrium condition once the disturbing action has ceased. Relaxation is the response of the system to the perturbation. The time required by the system to regain its condition of minimum energy is called the → relaxation time.
2) Math.: In numerical analysis, a method of solving equations in which the errors, or residuals, resulting from an initial approximation are reduced by succeeding approximations until finally all are within the toleration limit.

Verbal noun of → relax.

The characteristic length of time that is required for a system undergoing → relaxation to move to its equilibrium state. If the system follows an exponential law G = G₀ exp(-t / τ), the relaxation time is the time required for G to obtain the fraction 1/e of its initial value G₀.

→ relaxation; → time.

1) Control of the operation or performance of an apparatus from a distance, as the control of a guided missile by radio signals.
2) A device used to control the operation of an apparatus or machine, as a television set, from a distance.

→ remote; → control.

A mathematical process used in quantum physics that avoids infinite terms by carefully defining fundamental quantities such as mass and charge.

→ re-; → normalization.

The act of repeating; repeated action, performance, production, or presentation.

From L. repetitionem (nominative repetitio), from repetitus, p.p. of repetere "to do or say again."

Bâzgarš from bâz-, → re-, + garš "turn, time (indicating multiplication, as in three times, four times, etc.," aquivalent to Fr. fois), related to gez in hargez "ever, always; never," garz in hagarz "never." Garš has numerous variants in Pers. dialects, all denoting "turn, times" (بار، دفعه), e.g. [Mo'in]: gazak; Qâyeni: gaš; Hamadâni, Qomi: kaš; Lori: gey, gel; Semnâni, Sorxeyi, Lâsgardi, Sangesari: gazak; Gilaki: garaš; Tâleši: gara, vera, verxa; Tabari: gal, gel; Tâti Karingâni: kat; Kermâni: karet; related to Av. hakərət "once," from *ha(m)-kar-, the second element meaning "to do;" Pers; kardan; cf. Skt. sakrt "once, repeated; ever; never."

1) The act or the action of representing; the state of being represented.
2) The expression by some term, character, symbol, or the like.

M.E. representacion, from L. repraesentation, from repraesentatus p.p. of repraesentare, from → re- + praesentare "to show, give, present for approval," from praesens, from praeesse "to be before others, to be present," from prae- "before," → pre- + esse "to be," cognate with Pers. ast "is," astan, hastan "to be."

Nemâyeš, nemâyandegi, from nemudan "to show, demonstrate, exhibit," → display

1) The act of reproducing or the condition or process of being reproduced.
2) Something reproduced, especially in the faithfulness of its resemblance to the form and elements of the original.
3) Biology: Any of various processes, either sexual or asexual, by which an animal or plant produces one or more individuals similar to itself (TheFreeDictionary.com).

→ reproduce; → -tion.

Physics: The force that acts between bodies of like electric charge or magnetic polarity, tending to separate them.

Verbal noun of → repulse.

The act of resigning.

Verbal noun from → resign.

1) The degree to which an → optical system renders visible separate parts of an object. Also known as → angular resolution and → spatial resolution. See also → spectral resolution.
2) The time interval between successive discernible signals. → temporal resolution.

Verbal noun of → resolve.

Finding the → components of a → force which act in specified → directions.

→ resolution; → force.

1) The state of a → mechanical system in which the → amplitude of → oscillation is increased when it is subjected to stimulus from another source at or near its own natural → frequency.
2) The condition of an electrical circuit with respect to a given frequency in which the net reactance is zero and the current flow a maximum.
3) A relationship in which the → orbital period of one body is related to that of another by a simple integer fraction, such as 1/2, 2/3, 3/5. → Laplace resonance, → Lindblad resonance, → resonance orbit .
4) → resonance particle.

Resonance, from M.Fr. resonance, from L. resonantia "echo," from resonare "to resound," from re- "again, back" + sonare "to sound."

Bâzâvâyi, from bâz- "again, back," → re-, + âvâ "voice, sound" (related to âvâz "voice, sound, song," bâng "voice, sound, clamour" (Mid.Pers. vâng), vâžé "word;" Av. vacah- "word," vaocanghê "to decalre" (by means of speech), from vac- "to speak, say;" cf. Skt. vakti "speaks, says," vacas- "word;" Gk. epos "word;" L. vox "voice;" PIE base *wek- "to speak") + -yi noun suffix.

Capture by an atomic nucleus of a particle whose energy is equal to one of the energy levels of the nucleus.

→ resonance; → capture.

The frequency at which a system is in → resonance.

→ resonance; → frequency.

For a particular atom, the spectral line corresponding to the longest wavelength arising from a transition between the ground state and an excited state.

→ resonance; → line.

An orbit which is in → orbital resonance with another orbit.

→ resonance; → orbit.

A hadronic particle which exists for only a very brief time (10^-23 seconds) before decaying into hadrons; also called resonance. The existence of a resonance cannot be observed directly; it can only be inferred from studying the longer-lived products of its decay.

→ resonance; → particle.

A neutron with an energy between 1 eV and 0.01 MeV.

→ resonance; → region; → neutron.

Pertaining to a system in a state of → resonance; producing resonance; resounding.

Verbal adj. from → resonate.

An electrical circuit containing both capacitance and inductance in such a way that a certain periodic electric oscillation will reach maximum amplitude.

→ resonant; → circuit.