1) Light, downy particles, as of cotton.
Apparently a variant of floow "wooly substance, down, nap," perhaps from Flemish vluwe, from Fr. velu "shaggy, hairy," from L. vellus "fleece," or L. villus "tuft of hair" (Online Etymology Dictionary).
Kork "down, soft wool, fluff," of unknown etymology.
Fr.: duveteux, bouffant
Of, resembling, or covered with fluff.
Korkvâr "resembling fluff," with -vâr, a suffix of possession, similarity, and aptitude (e.g., omidvâr, sezâvâr, sugvâr, šâhvâr, gušvâr), → -oid; korki adj. with -i.
fluffy dust grain
dâne-ye qobâr-e korkvâr
Fr.: grain de poussière duveteux
An aggregate of small particles loosely stuck together. Same as → porous dust grain.
A continuous, amorphous substance whose molecules move freely past one another and that has the tendency to assume the shape of its container; collective term for liquids and gases.
From L. fluidus "fluid, flowing," from fluere "to flow;" → flux.
Šârré, from šârr, → flux.
Fr.: dynamique des fluides
The branch of → fluid mechanics that deals with the movement of gases and liquids.
Fr.: mécanique des fluides
The ability of a substance to flow; reciprocal of → viscosity.
Process in which photons of lower energy are emitted as the result of absorption of energy by an atom or molecule from other radiation. The phenomenon lasts as long as the stimulus responsible for it is present. → phosphorescence.
Coined by E. mathematician and physicist Sir George G. Stokes (1819-1903) from fluor- (from fluorspar "a mineral composed of calcium fluoride, CaF2, also called fluorite, that is often fluorescent under ultraviolet light") + -escence a suffix of nouns denoting action or process, change, state or condition, etc.
Angiztâbi, from angiz present stem of angixtan→ excite + tâb "light; heat, warmth; illuminating," from tâbidan, tâftan "to shine," tafsidan "to become hot" (Av. tāp-, taf- "to warm up, heat," tafsat "became hot," tāpaiieiti "to create warmth;" cf. Skt. tap- "to spoil, injure, damage; to suffer; to heat, be/become hot," tapati "burns;" L. tepere "to be warm," tepidus "warm;" PIE base *tep- "warm") + -i noun suffix.
Fr.: ampoule fluorescente
A tubular electric discharge lamp in which light is produced by the fluorescence of phosphors coating the inside of the tube.
A compound (salt of hydrofluoric acid) containing → fluorine.
Gaseous chemical element; symbol F. It is the most reactive of all chemical elements. It is a yellowish, corrosive gas, which reacts with most organic and inorganic substances. → Atomic number 9; → atomic weight 18.9984; → melting point -219.62 °C; → boiling point -188.14 °C; → density 1.696 grams per liter at STP; → valence -1. Fluorine and its compounds are used in producing uranium (from the → hexafluoride) and more than 100 commercial fluorochemicals, including many high-temperature plastics.
From L. fluere "flow, → flux," since fluorspar (CaF2) was used as a flux in metallurgy because of its low melting point. It was discovered in hydrofluoric acid by the Swedish pharmacist and chemist Carl-Wilhelm Scheele in 1771 but it was not isolated until 1886 by the French pharmacist and chemist Ferdinand Moisson.
The amount of energy, fluid, or particles passing in a given direction in a unit of time.
O.Fr. flux, from L. fluxus, p.p. of fluere "to flow," PIE base *bhleug- (cf. L. flumen "river;" Gk. phluein "to boil over, bubble up," phlein "to abound").
Šâr "outpouring of water, wine, etc.," šâridan "to flow (as river) with a great noise; to pour," âbšâr "waterfall;" Ossetic ægzælyn "to pour down;" Av. γžār- "to flow;" cf. Skt. ksar- "to flow;" Gk. phtheirein "to destroy, perish."
Fr.: calibration de flux
The → calibration of the flux received by a detector in terms of absolute units.
Fr.: densité de flux
Flux of radiation that falls on a detector per unit surface area of the detector per unit bandwidth of the radiation per unit time.
Fr.: unité de flux
In radio astronomy, same as → jansky (symbol Jy), a unit of electromagnetic flux equivalent to 10-26 watts per square meter per Hertz.
parvâz kardan (#), parvâzidan (#)
To move through the air using wings. Travel through the air or outer space.
M.E. flien, O.E. fleogan; cognate with O.H.G. fliogan, Ger. fliegen, O.Norse fljuga.
Infinitive from parvâz, → flight.
A trajectory that takes a → space probe close to a Solar System body (planet, satellite, asteroid, comet) but does not permit it to enter an orbit about the body.
→ fly + by, from M.E., from O.E. be or bi, from P.Gmc. *bi "around, about" (cf. Du. bij, Ger. bei "by, at, near"), from *umbi, (cf. L. ambi "around, about," Gk. amphi "around, about," Skt. abhi "on both sides," Av. aibi, aiwi, O.Pers. aiby "to, against, in addition to," Mid.Pers. aw-, ab-, Mod.Pers. af- (as in afzudan "to increase, add," afruxtan "to inflame, kindle, blaze," afqân "lamentation, groaning, cires for help").
Of or relating to a focus; placed at or measured from a focus.
Fr.: distance focale
same as → focal length.
Fr.: longueur focale
The distance between the optical center of a lens, or the surface of a mirror, and its focus.