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

The opposition to the flow of alternating current caused by the inductance and capacitance in a circuit rather than by resistance.

From → react + -ance a suffix of nouns.

Vâžirâyi state noun of vâžirâ agent noun of vâžiridan→ react.

1) General: A person or thing that reacts.
2) A substance on the left side of a → chemical equation.

From → react + -ant.

1) General: Action in response to some influence, event, stimulus.
2) An equal and opposite force exerted by a body against a force acting upon it. → principle of action and reaction.
3) A → nuclear reaction; → chain reaction.
4) → chemical reaction.

Verbal noun of → react.

The speed with which a → chemical reaction takes place. In other words, the change in → concentration of a → substance divided by the → time interval during which the change is observed.

→ reaction; → rate.

Tending to react. Pertaining to or characterized by reaction.

From → react + -ive a suffix of adjectives expressing tendency, disposition, function, connection, etc.

Vâžirandé verbal adj. of vâžiridan→ react; vâžireši, adj. of vâžireš→ reaction.

1) General: The quality or condition of being reactive.
2) Physics: A measure of the deviation from the condition at which a → nuclear reactor is critical.
3) Chem.: The relative → capacity of an → atom, → molecule, or → redical to undergo a → chemical reaction with another atom, molecule, or → compound.

From → reactive + → -ity.

1) A device for introducing reactance into an electrical circuit (e.g. a capacitor).
2) Same as → nuclear reactor.

From → react + → -or.

The part of a → nuclear reactor in which → nuclear fission takes place and huge quantities of heat energy are generated.

→ reactor; → core.

In computing and data processing, the number of words, characters, fields, etc. sensed by an input sensing device per unit of time.

Reading, verbal noun of read, from M.E. reden, O.E. rædan, redan "to counsel, read;" cf. Du. raden, Ger. raten "to advise, counsel, guess;" akin to Skt. rādh- "to succeed, accomplish;" Gk. arithmos "number amount;" L. ratio; Pers. rây, râ "because of, for the sake of;" → reason; → rate.

Nerx, → rate; xâneš verbal noun of xândan "to read; to sing; to call;" Mid.Pers. xwân- "to resound; to call;" Av. x^van- "to sound," Proto-Iranian *huan- "to call;" cf. Skt. svan-, sváranti "to sound, make a sound, sing;" L. sonus "sound," sonare "to sound;" O.E. swinn "music, song," PIE base *suen- "to sound" (Cheung 2007).

The noise added in the process of reading a detector such as a CCD.

→ reading rate; → noise.

A chemical substance that, because of the reactions it causes, is used to detect, measure, or prepare another substance.

From re(act) + → agent.

Vâkonešgar, from vâ-, → re-, + konešgar→ agent.

1) General: Having actual physical existence; genuine, not artificial.
2) Math.: Involving, relating to, or having elements of the set of rational or irrational numbers only.
3) Philo.: Existent or pertaining to the existent as opposed to the nonexistent; actual as opposed to possible or potential.
See also:
→ real dynamical variable, → real equator, → real equinox, → real fluid, → real gas, → real image, → real number, → real object, → real-time operation, → real-time processing, → realism, → realist, → realistic, → reality, → true.

M.E., from O.Fr. reel, from L.L. realis "relating to things; actual," from L. res "matter, thing," of unknown origin.

Hasyâ, from O.Pers. hašya- "true, real;" Av. haiθa- "true, real;" cf. Khotanese hiththo "true, real;" Ossetic aecaeg "true, real, genuine;" Skt. satyá- "true, real, genuine;" PIE base *es- "to be" (Mod.Pers. hastan, astan "to be;" O.Pers./Av. ah-, Skt. as-).

A → dynamical variable which does not have an → imaginary number part.

→ real; → dynamical; → variable.

Same as → true celestial equator.

→ real; → equator.

Same as → true equinox.

→ real; → equinox.

The opposite of an ideal fluid; a fluid which possesses viscosity and therefore exhibits certain frictional phenomena. Viscosity arises due to cohesive forces between molecules and molecular momentum exchange between fluid layers. These effects appear as tangential or shear stresses between moving fluid layers.

→ real; → fluid.

Actual gas whose molecules do not necessarily possess the properties assigned to those of an → ideal gas.

→ real; → gas.

In an optical system, the image of an object produced by the convergence of the light rays that make up the image. → virtual image; → real object.

→ real; → image.

A number that can be represented by a point on a line. The set of real numbers includes all rational and irrational numbers, but not the imaginary numbers.

→ real; → number.

In an optical system, a collection of points which actually serves as a source of light rays.

→ real; → object.