# An Etymological Dictionary of Astronomy and AstrophysicsEnglish-French-Persian

## فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

### M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 9 Search : section
 collisional cross section   سکنج ِ اسکرمند ِ همکوبشی   sekanj-e oskarmand-e hamkubešiFr.: section efficace de collision   Same as → cross section.→ collisional; → cross; → section. conic section   سکنج ِ مخروطی   sekanj-e maxrutiFr.: section conique   A curve which may be represented as the intersection of a plane with a cone; hence a → parabola, → hyperbola, or → ellipse.→ cone; → section. cross section   سکنج‌گاه   sekanjgâhFr.: 1) section plane; 2) section efficace   1) Math: The intersection of a plane with a geometric figure, usually at right angles to an axis of symmetry. 2) Physics: A quantity that expresses the effective area that a given particle presents as a target to another incident particle, giving a measure of the probability that the incident particle will induce a particular atomic or nuclear reaction. Also called collision cross section. The cross section has the dimensions of a surface. In nuclear and particle physics, the commonly used units for the cross section are the barn and cm2.In classical mechanics, the cross section for the collision of a point particle with a hard sphere is just be the surface of a section through the middle of the sphere. This explains the name "cross section." → cross; → section. dissection   واسکنجش   vâsekanješFr.: dissection   The act of dissecting.→ dissect; → -tion. intersection   اندربرش، اندرسکنج   andarboreš, andarsekanjFr.: intersection   The act, process, or result of intersecting.Math.: A set of elements common to sets A and B, denoted by A ∩ B. → section.Verbal noun of → intersect. minimum orbit intersection distance (MOID)   دورای کمینه‌ی ِ اندرسکنج ِ مدار   durâ-ye kamine-ye andarsekanj-e madârFr.: distance minimale d'intersection d'une orbite   The minimum distance between the paths of two orbiting objects around a → primary. Such distance between an object and Earth is called Earth MOID.→ minimum; → orbit; → intersection; → distance. nuclear cross-section   سکنج‌گاه ِ هسته‌ای   sekanjgâh-e hasteyiFr.: section efficace nucléaire   Apparent cross-section possessed by an atomic nucleus when it undergoes a particular type of collision process.→ nuclear; → cross section. section   سکنج   sekanj (#)Fr.: section   A part that is cut off or separated. A distinct part or subdivision of anything. → cross section; → intersectionFrom M.Fr. section, from L. sectionem "a cutting, division," from secare "to cut;" PIE base *sek- "cut" (cf. O.C.S. seko, sesti "to cut," Lith. isekti "to engrave, carve;" O.S. segasna, O.E. sigðe "scythe;" O.E. secg "sword," seax "knife, short sword").Sekanj "a scraping, shaving, cutting," cognate with Pers. šekast-, šekastan "to break;" Av. skand- "to break," Skt. khand- "to break," khanda- "piece;" Pers. dialect Tabari šag "a special razor used to make incisions in the walls of unripe opium poppies in order to extract the milky sap," may be related to PIE *sek- "cut," as above. Thomson cross section   سکنج‌گاه ِ تامسون   sekanjgâh-e ThomsonFr.: section efficace de Thomson   The → cross section involved the → Thomson scattering of electromagnetic waves by a free electron. It is defined by: σT = 8πre2/3, where re is the classical → electron radius. Its value is 0.665 245 x 10-28 m2.→ Thomson; → cross; → section.