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ethno- qowm- (#) Fr.: ethno- A combining form meaning "race, culture, people." From Gk. ethnos "people, nation, class, tribe." Qowm- loan from Ar. qaum "people, tribe, family." |
ethnoastronomy qowm-axtarshenâsi Fr.: ethnologie The study of the beliefs, interpretations, and practices of specific cultures regarding celestial objects or phenomena. Ethnoastronomy uses the tools and methodologies of → ethnology in the study of astronomical conceptions. |
ethnology qowmšenâsi Fr.: ethnologie The study of specific cultures (ethnic groups) in their different aspects (anthropological, social, cultural, etc.) to establish similarities and disparities between them. |
ethyl etil (#) Fr.: éthyl A chemical group, C_{2}H_{5}, produced by removing a hydrogen atom from → ethane. For example, ethyl chloride is C_{2}H_{5}Cl From Ger. Ethyl, from eth-, from → ether, + -yl a suffixed used in the names of radicals. |
ethyl alcohol etil alkol (#) Fr.: éthyl alcool Same as → ethanol. |
etymology riše-šenâsi (#) Fr.: étymologie The study of the origins and history of the form and meaning of → words. M.E., from L. etymologia, from Gk. etymologia, from etymon "true sense" (neuter of etymos) + logos, → -logy. Riše-šenâsi, from rišé "root" (dialectal Tabari rexa; Kurd. regez, riše), from Mid.Pers. rêšak "root," maybe ultimately related to PIE *u(e)rad-, although the Skt. offshoot is absent (Gk. rhiza "root;" L. radix, radius "staff;" O.H.G. wurz "plant, herb;" Ger. Wurz; O.E. rot; E. root) + -šenâsi, → -logy. |
eu- hu- (#) Fr.: eu- A prefix meaning "good, well; true, genuine" (eupepsia; eukaryote); opposed to → dys-. L. from Gk. eu "well," combining form of eus "good" (hu-gies "healthy"); cf. Mid.Pers. hu-; Av. hu- "good;" PIE base *su- "good," see below. Mid.Pers. hu- "good, well" (hu-boy "sweet-smelling," hu-cihr "beautiful," hu-mânih "good-mindedness"); O.Pers. ^{h}u- "good, well" (ukāra- "having good people"); Av. hu-, hū- "well, good, beautiful" (hu-kərp- "well-shapen," hūxta- "well spoken," hu-manah- "good-minded"); Skt. su- "good" (svasti "well-being, good luck," sumánas- "good-minded," sūktá- "well spoken"); Gallic su-; O.S. su-; Welsh hy-; PIE base *su-, as above. |
Euclidean Oqlidosi (#) Fr.: euclidien Of or pertaining to Euclid, or his postulates. → Euclidean division, → Euclidean geometry, → Euclidean space, → non-Euclidean geometry. After the Gk. geometrician and educator at Alexandria, around 300 B.C., who applied the deductive principles of logic to geometry, thereby deriving statements from clearly defined axioms. |
Euclidean division baxš-e Oqlidosi Fr.: division euclidienne In arithmetic, the conventional process of division of two → integers. For a → real number a divided by b > 0, there exists a unique integer q and a real number r, 0 ≤ r <b, such that a = qb + r. |
Euclidean geometry hendese-ye Oqlidosi (#) Fr.: géométrie euclidienne The geometry based on the postulates or descriptions of Euclid. One of the critical assumptions of the Euclidean geometry is given in his fifth postulate: through a point not on a line, one and only one line be drawn parallel to the given line. See also → non-Euclidean geometry. |
Euclidean space fazâ-ye Oqlidosi Fr.: espace euclidean A space in which the → distance between any two points is given by the → Pythagorean theorem: d^{2} = (Δx)^{2} + (Δy)^{2} + (Δz)^{2}, where d is distance and Δx, Δy, and Δz are differential → Cartesian coordinates. Euclidean n-space R^{n} is the set of all column vectors with n real entries. |
Eudoxan spheres sepehrhâ-ye Eudoxus Fr.: sphères d'Eudoxe |
Euler Euler Fr.: Euler Leonhard Euler (1707-1783), the eminent Swiss mathematician, physicist, and astronomer. |
Euler equation hamugeš-e Euler Fr.: équation d'Euler In → fluid mechanics, one of a set of → differential equations that govern the motion of a → compressible, → inviscid fluid. Euler equations correspond to the → Navier-Stokes equations with zero → viscosity. |
Euler line xatt-e Euler Fr.: droite d'Euler In any → triangle, the straight line on which always lie the → centroid, → circumcenter, and → orthocenter. |
Euler's broken line xatt-e šekaste-ye Euler Fr.: ligne brisée The line drawn in a coordinate plane connecting the approximate values of the solution of a → first-order differential equation. → Euler; → broken line. |
Euler's formula disul-e Euler Fr.: formule d'Euler A formula which expresses an → exponential function
with an → imaginary number
→ exponent in terms of
→ trigonometric functions: |
Eulerian method raveš-e Euleri Fr.: méthode eulérienne Fluid mechanics: A method in which the changes in the physical properties of the fluid, such as velocity, acceleration, and density are described at a fixed point in space occupied by the fluid. Compare with → Lagrangian method. |
euphemism xošguyi, xošzabâni Fr.: euphémisme An inoffensive word or phrase substituted for one considered offensive or hurtful, especially one concerned with religion, sex, death, or excreta (TheFreeDictionary.com). From Gk. euphemismos, from euphemizein "speak with fair words, use words of good omen," from → eu- "well," + pheme "speech, voice, talk," from phanai "to speak," ultimately from PIE *bha- "to speak, tell, say;" cf. Skt. bhanati "speaks;" L. fari "to say," fabula "tale, story," fama "talk, rumor, report; reputation;" Armenian ban, bay "word, term." Xošguyi, xošzabâni, literally "pleasant talking, ~ speach," from xoš "well, pleasant," → eu- + guyi verbal noun of goftan "to say, talk, speak," → logic; zabâni, from zabân, → language. |
Europa (Jupiter II) Europâ, orupâ (#) Fr.: Europe The sixth of → Jupiter's known moons and the fourth largest; it is the second of the → Galilean satellites. With a diameter of 3140 km, Europa is slightly smaller than Earth's Moon. Its mass is 4.80 × 10^{22} kg, i.e. 1.5 times less massive than Earth Moon. Its distance to Jupiter is 670,900 km, or about 9 Jovian radii. Its → orbital period is 3.55 Earth days which equals its → rotation period. Europa's density is 3.0 g cm^{-3}, typical of a mixture of rocks including → ice. Its high → albedo (0.67) suggests that its surface is mostly → water ice. The → surface temperature of Europa ranges between about 125 K (-150 °C) at the equator and about 50 K (-220 °C) at the poles. There are few → impact craters on Europa, because its surface is too active and therefore young. The most striking features of Europa's surface are structures called → lineae and → lenticulae. The thickness of the ice crust could range between a few kilometers to a few tens of kilometers. It is now believed that there is an ocean of salty water, up to 100 km deep, flowing under Europa's ice. Europa's ocean is kept liquid due to → tidal heating by Jupiter. In Gk. mythology, Europa was a Phoenician princess (Agenor's daughter) abducted to Crete by Zeus, who had assumed the form of a white bull, and by him the mother of Minos, Sarpedon, and Rhadamanthys. |
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