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

An ecological concept, the property or condition of being → sustainable.

Quality, state noun from → sustainable.

Ecology: Maintaining ecological balance; exploiting natural resources without destroying the ecological balance of an area, e.g. → sustainable agriculture; → sustainable development.

→ sustain; → -able.

The ability of a farm to produce food indefinitely, without causing severe or irreversible damage to → ecosystem health.

→ sustainable; → agriculture.

Ecology: A development that meets the needs of the present without compromising the ability of future generations to meet their own needs.

→ sustainable; → development.

A large, usually white bird with a long neck that lives on rivers and lakes (family Anatidae, especially genus Cygnus).

M.E., from O.E. swan; cf. O.S. swan, O.N. svanr, M.Du. swane, Du. zwaan, O.H.G. swan, Ger. Schwan, probably literally "the singing bird," from PIE base *swon-/*swen- "to sing, make sound."

Qu "swan," maybe an onomatopoetic word from the sound of swan's call; cf. Russ. ky-ky "cry of a swan."

One of the three prominent bands in the spectra of comets and carbon stars caused by diatomic carbon (C₂).

Named after the Scottish physicist William Swan (1818-1894) who first studied the spectral analysis of radical carbon C₂ in 1856; → band.

Same as → Omega Nebula.

→ swan; → nebula.

A great number of things especially in motion. → meteorite swarm.

ME; OE swearm; cf. O.S., M.L.G. swarm, Swed. svärm, M.Du. swerm, O.H.G. swarm, Ger. Schwarm "swarm;" O.N. svarmr "tumult."

Qang in Lârestâni "swarm of bees, flies, or the like," Lori qem (qem zaye) "swarm of bees, ants, and the like."

The → radius of a → supernova remnant (SNR) when, at the end of the → free expansion phase, the mass of the swept-up → shell equals that of the ejected gas from the → supernova explosion. It is given by R_SW = (3M_e / 4πρ₀)^(1/3), where M_e is the ejected mass and ρ₀ is the initial density of the → interstellar medium.

Sweep, from M.E. swepen, from O.E. swapan "to sweep;" cognate with Ger. schweifen; → up; → radius.

Šo'â', → radius; rubeš, noun from ruftan, rubidan "to sweep," → scan.

1a) A shift from one to another.
1b) A device used to break or open an electric circuit or to divert current from one conductor to another.
2) To shift or exchange; To connect, disconnect, or redirect.

Switch "slender riding whip, flexible stick," probably from a Flemish or Low German word akin to Hanoverian swutsche, a variant of Low Ger. zwukse "long thin stick, switch."

Degarbân, from degar "other, another" (Mid.Pers. dit, ditikar "the other, the second;" O.Pers. duvitiya- "second," Av. daibitya-, bitya- "second;" Skt. dvitiya- "second," PIE *duitiio- "second") + -bân a suffix denoting "keeper, guard," sometimes forming agent nouns or indicating relation, → host.

The act of changing one thing or position for another.

Verbal noun of → switch (v.).

1) A weapon having various forms but consisting typically of a long, straight or slightly curved blade, sharp-edged on one or both sides, with one end pointed and the other fixed in a hilt or handle (Dictionary.com).
2) → Orion's Sword.

M.E.; O.E. sweord; cognate with Du. zwaard, Ger. Schwert, Sw. svärd.

Šamšir, Mid.Pers. šamšêr / šamšyl, Parthian safsêr; cf. Gk. sampsera denoting a "foreign sword." The E. scimitar derives ultimately from šamšir through M.Fr. cimeterre or directly from It. scimitarra, possibly from an unknown Ottoman Turkish word, borrowed from Pers.

A kind of → deductive reasoning whereby from two initial → propositions (two → premises) a third related proposition (→ conclusion) is derived. The typical form of a → categorical syllogism is "A is B;" "C is A;" "Therefore, C is B." For example, "All humans are mortal." "John is human." "Therefore, John is mortal." "Mortal" (B) is called the → major term; it occurs in the first premise and is the → predicate of the conclusion. "John" (C), the subject of the conclusion, is called the → minor term. "Human," which is common to both premises and is excluded from the conclusion, is called the → middle term. See also → Aristotelian forms. Syllogism is purely formal. It does not enrich knowledge, but gives a new presentation to what is already known. It is also possible to have a logically valid syllogism based on → absurd premises. For example, "All cats are mammals." "All cats are animals." "Therefore, all animals are mammals." Syllogism, representing the earliest branch of → formal logic, was developed in its original form by Aristotle in his Organon (Prior Analytics) about 350 BC.
See also: → bivalent logic, → polyvalent logic, → symbolic logic, → propositional logic, → first-order logic, → predicate logic, → syllogistic; → fuzzy logic.

M.E. silogisme, from O.Fr. silogisme, from L. syllogismus, from Gk. syllogismos "a syllogism," originally "inference, conclusion; computation, calculation," from syllogizesthai "bring together before the mind, compute, conclude," from assimilated form of → syn- "together" + logizesthai "to reason, to count," from logos "a reckoning, reason," → logic.

Bâhamšomârik, literally "reckoning together," from bâham "together," from bâ "with," → hypo-, + ham, → syn-, + šomâr present stem of šomârdan "to reckon, calculate, enumerate, account for," → count, + suffix -i.

1a) Of or pertaining to a → syllogism.
1b) Like or consisting of syllogisms.
2a) The part of logic that deals with syllogisms.
2b) Syllogistic reasoning (Dictionary.com).

→ syllogism; → -ic.

Of or pertaining yo symbiosis in biology, denoting a close, prolonged association between two or more different organisms of different species that may be, but does not necessarily, of mutual benefit. → symbiotic star.

From Mod.L., from Gk. symbiosis "a living together," from symbioun "live together," from symbios "(one) living together (with another), partner," from → syn- "together" + bios "life," → bio-.

Hamzi "living together," from ham- "together," → syn-, + zi- present stem of zistan "to live," → bio-.

A → B[e] star whose spectrum shows the presence of a cool component characterized mainly by → TiO bands.

→ symbiotic; → B[e] star.

A stellar object whose optical spectrum displays lines characteristic of gases of two very different temperatures, typically of an M star (3500 K) and a B star (20 000 K) superimposed. A symbiotic star is in fact a close binary system.

→ symbiotic; → star.

1) Something that stands for or represents something else, especially an object representing an abstraction.
2) A conventional sign or character that represents something in a specific context, e.g. an operation or quantity in mathematics or music.

M.E., from L.L. symbolum "creed, token, mark," from Gk. symbolon "sign, mark," from → syn- "together" + stem of ballein "to throw."

Namâd variant of namud, nemud past stem of nemudan "to show;" Mid.Pers. nimūdan, nimây- "to show," from O.Pers./Av. ni- "down; into," → ni- (PIE), + māy- "to measure;" cf. Skt. mati "measures," matra- "measure;" Gk. metron "measure;" L. metrum; PIE base *me- "to measure."

Of or relating to a symbol or symbols; serving as a symbol.

→ symbol; → -ic.

A modern development of → formal logic based on a system of → symbols and → axiomatics in accordance with precise rules. It uses a formalized → artificial language to avoid the ambiguities and logical inadequacies of → natural languages. Symbolic logics are → polyvalent when they admit → truth values other than → true and → false.

→ symbolic; → logic.