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

The difference between the number of neutrons in an isotope and the number of protons. Neutron excess.

→ isotopic; → number.

The relative abundances of two isotopes of a given chemical element, such as D/H (deuterium/hydrogen), (carbon) ¹²C/¹³C, and (uranium) ²³⁵U/²³⁸U.

→ isotopic; → ratio.

Same as → isospin.

→ isotopic; → spin.

Any of molecular entities which differ in their isotopic composition but retain the same → chemical elements, e.g. H₂O and HDO.

Abbreviation of → isotopic → analogue.

Any of → isomers having the same number of each isotopic atom but differing in their positions. For example, CH₃CHDCH₃ and CH₃CH₂CH₂D are a pair of isotopomers.

Short for isotopic isomers.

Having physical properties that do not vary with direction.

→ iso- + → -tropic.

A Universe having observed properties that appear identical in every direction.

→ isotropic; → universe.

The property by which physical properties are equal along all directions. → anisotropy.

Isotropy, noun of → isotropic.

1a) A result or outcome of something.
1b) The action of flowing or coming out.
1c) Each of a regular series of publications.
1d) An important topic or problem for debate or discussion.
2) Formally send out or make known (OxfordDictionaries.com).

M.E., from O.Fr. issue "a way out, a going out, exit; final event," from L. exire "to go out, go forth; become public; flow, pour forth," from → ex- "out," + ire "to go,"

Borunây, literally "what comes out, exits," from borun, → out, + ây- present stem of âmadan "to come, arrive, become," → precession.

1) To utter or to do something over again or repeatedly. → repeat.
2) Math.: → iteration.

Iterate "to do again, repeat," back-formation from iteration, from L. iterationem (nom. iteratio) "repetition," noun of action from iterare "to do again, repeat," from iterum "again, for the second time;" cf. Skt. itara- "the other (of the two), another."

Itaridan, from L. iter(um), Skt. itar(a-), as above, and Pers. dialects Kâšâni (Voništun) târ "the other;" Kurd. tir "the other" + -idan Pers. infinitive suffix.

A computational process involving a succession of approximations, which consists of repeating the operation by inputting the outcome of each preceding operation to improve the final result until a desired accuracy is achieved. Compare → repetition.

Verbal noun of → iterate.

A method of computation in mathematics using → iteration.

Iterative, characterized by or involving → iteration; → method.

A bright giant star in the constellation → Boötes lying 210 light-years away. It is a close double consisting of K0 and A0 dwarfs of magnitudes 2.5 and 4.6.

From Ar. Al-Izâr (الازار) "a cloth worn round the loins and passed between the legs," Ar. rendering of the Herdsman's skirt; → Boötes.