Fr.: seuil d'énergie
The minimum energy necessary for the occurrence of some chemical/physical effect.
threshold of reaction
Fr.: seuil de réaction
The minimum energy, for an incident particle or photon, below which a particular reaction does not occur.
Fr.: seuil de signal
The minimum intensity of a signal that can be detected and recognized.
The front part of the neck. → nozzle throat.
M.E. throte, O.E. throte, throta, throtu; cognate with O.H.G. drozza "throat," O.N. throti "swelling."
Galu "throat," related to geri, geribân "collar," gerivé "low hill," gardan "neck;" Mid.Pers. galôg, griv "throat," gartan "neck;" Av. grīvā- "neck;" cf. Skt. gala- "throat, neck;" Gk. bora "food;" L. gula "throat" (Fr. gueule "(animal) mouth"), gluttire "to gulp down," vorare "to devour;" PIE base *gwer- "to swallow, devour." L. gula; cf. Mod.Pers. galu "throat,"
A jointed ring placed at the upper end of a → planispheric astrolabe astrolabe. By slipping one's thumb into the ring, one raises the instrument so that its weight and symmetrical design keeps it perpendicular to the ground (online museo galileo, VirtualMuseum).
From L. thronus, from Gk. thronos "elevated seat, chair, throne," from PIE root *dher- "to hold firmly, support;" cf. L. firmus "firm, steadfast, strong, stable," Skt. dharma- "statute, law;" Pers. dâr-, dâštan "to have, to possess," → property.
Korsi "throne, chair, seat," from Ar. kursī.
Fr.: 1) étrangler, serrer la gorge de; 2) mettre au ralenti
1a) To stop the breath of by compressing the throat; strangle.
M.E. throtelen, from throten "to cut the throat of (someone), strangle," from → throat.
Tâsenidan, from Dezfuli tâsenidan "to choke, compress the throat," cf. Laki, Šuštari tâsenan "to strangle," Ilâmi tâsânen "to strangle," Baxtiyâri tâsest "suffocated," Fini Bandar-Abbâs tâsaki "exhausted," (Dehxodâ) tâsidan "to be afflicated or sad," tâsidé "tired, emaciated," Baluci ta(n)sit "to be out of breath, pant;" Skt. tam- "to become suffocated, exhausted;" L. temulentus "drunken;" PIE *temH- "to faint, be exhausted" (Cheung 2007).
Fr.: 1) détente Joule-Thomson
1) Thermodynamics: A process in which a gas, originally at a constant high
pressure, passes → adiabatically
through a porous wall or a narrow opening into a region of constant lower
pressure. The throttling process is → irreversible
and is accompanied by an increase of → entropy.
The → enthalpy of the gas is the same in the
→ initial and
→ final → states.
Also called → Joule-Thomson expansion.
The change in the temperature of the gas in throttling is known as
the → Joule-Thomson effect.
Fr.: à travers
1) In at one end, side, or surface and out at the other.
M.E. (preposition and adv.), metathetic variant of thourgh, O.E. thurh, (cognates O.S. thuru, OFris. thruch, Du. door, O.H.G. thuruh, Ger. durch), cognate with Av. tarô, tarə "over, across, beyond," L. trans-, → trans-.
Târu, related to tarâ-, → trans-, and from Av. tarô, tarə, as above.
To propel something through the air in any way, especially by swinging the arm and releasing the object from the hand; → ejecter.
M.E. throwen, thrawen, "to twist, turn writhe" (cf. O.S. thraian, M.Du. dræyen, Du. draaien, O.H.G. draen, Ger. drehen "to turn, twist").
Andâxtan, andâz-, from Mid.Pers. handâxtan, handâz-; ultimately from Proto-Iranian *ham-tak-, from *ham- "together, with, same," → syn- + *tak- "to run, to flow;" cf. Av. tak- "to run, to flow," taciāp- "flowing water," tacinti (3pl.pers.act.) "to flow," tacar- "course," tacan "current, streaming;" Mod.Pers. tacidan, tâxtan, tâzidan "to run; to hasten; to assault," tajan name of a river (initially "flowing, streaming, stream"), tâzi "swift (greyhound)," tak "running, rush," from Mid.Pers. tâz-, tâxtan "to flow, to cause to walk," tc- "to flow, to walk," tag "running, attack," tâzig "swift, fast;" Khotanese ttajs- "to flow, to walk;" Skt. tak- to rush, to hurry," takti "runs;" O.Ir. tech- "to flow;" Lith. teketi "to walk, to flow;" O.C.S. tešti "to walk, to hurry;" Tokharian B cake "river;" PIE base *tekw- "to run; to flow.
M.E. thrusten, thrysten (v.); O.N. thrysta "to thrust, force."
Pišrâné, from piš "before; in front" (Mid.Pers. pêš "before, earlier," O.Pers. paišiya "before; in the presence of") + râné, from rândan "to push, drive, cause to go" (causative of raftan "to go, walk, proceed," present tense stem row-, Mid.Pers. raftan, raw-, Proto-Iranian *rab/f- "to go; to attack").
A fourth magnitude star (V = 3.65), called also α Draconis, in the constellation → Draco. Despite its designation as Alpha (α), it is the seventh brightest star of the constellation. Thuban is a → giant star of → spectral type A0 III lying 310 → light-years away. It has an faint → companion in an orbit with a 51 day period. Thuban was the → pole star at about 2700 BC. Other designations: HR 5291, HD 123299, and SAO 16273.
Thuban, from Ar. Ath-thu'bân (
A soft, malleable, ductile, lustrous silver-white metal; symbol Tm. Atomic number 69; atomic weight 168.9342; melting point about 1,545°C; boiling point 1,947°C; specific gravity 9.3. Thulium was discovered in 1879 by the Swedish chemist Per Theodor Cleve in a sample of erbium mineral. It was first isolated by the American chemist Charles James in 1911.
From Thule, the earliest name for Scandinavia.
A loud rumbling sound emitted by rapidly expanding air along the path of the electrical discharge of lightning.
M.E. thonder, thunder, O.E. thunor, from P.Gmc. *thunraz (cf. O.Fris. thuner, M.Du. donre, Du. donder, O.H.G. donar, Ger. Donner "thunder"), cognate with Pers. tondar, as below.
Tondar; Mid.Pers. tndwr, Sogdian twntr; cf. Skt. stan- "to thunder, resound," tanyati "thunders, roars," tanyu- "thundering," stanatha- "thunder;" L. tonare "to thunder," tonitrus "thunder" (Fr. tonnerre); PIE base *(s)tene- "to resound, thunder."
tondar-tuf, tufân-e tondari
A → storm of → thunder and → lightning. Thunderstorms are associated with → convective clouds (Cumulonimbus) and are often accompanied by → precipitation. They are usually short-lived and hit on only a small area.
Tondar-tuf, tufân-e tondari, from tondar, → thunder + tuf stem of tufidan "to roar, to raise a tumult," tufân "storm, the roaring of the sea, the confused hum of men or animals." This Persian word may be related to Gk. typhon "whirlwind, mythical monster associated with tempests."
1) sof; 2) sofidan
Fr.: 1) coche; 2) cocher
1) A small dot, mark, check, or electronic signal, as used to mark off an
item on a list, serve as a reminder, or call attention to something (Dictionary.com).
M.E. tek "little touch," akin to Du. tik "a touch, pat," M.H.G. zic.
Sof, sofidan, related to sufâr "the groove at the end part of an arrow," → nock, on the model of Fr. coche "notch, score."
Fr.: de marée
Of, pertaining to, characterized by, or subject to → tides.
Adj. from kašand, → tide.
Fr.: freinage des marées
The physical process that slows the → Earth's rotation rate due to → tidal friction. The → Earth rotates faster than the → Moon orbits the Earth (24 hours compared to 27 days). The → friction between the ocean and the solid Earth below drags the → tidal bulge ahead of the line joining the Earth and the Moon. The → gravitational attraction of the Moon on the bulge provides a braking action on the Earth and decelerates its rotation. Tidal braking lengthens the day by 0.002 seconds every century. Because the total → angular momentum of the → Earth-Moon system in conserved, the loss in the angular momentum of the Earth is compensated by the orbital angular momentum of the Moon. Hence, the Moon moves away from Earth at a rate of about 3 cm per year. This process must continue until Earth's → day and → month are equal, at which point the Moon will never seem to move in Earth's sky and Earth is said to be tidally locked to the Moon (→ tidal locking).
Fr.: bourrelet de marée
Either of the two swells of land or water (on Earth) created by the pull of another object (Moon) orbiting around it. The → gravitational attraction between the → Earth and the → Moon is strongest on the side of the Earth that happens to be facing the Moon. This attraction causes the water on this "near side" of Earth to be pulled toward the Moon. As gravitational force acts to draw the water closer to the Moon, → inertia attempts to keep the water in place. But the gravitational force exceeds it and the water is pulled toward the Moon, causing a "bulge" of water on the near side toward the Moon. On the opposite side of the Earth, or the "far side," the gravitational attraction of the Moon is less because it is farther away. Here, inertia exceeds the gravitational force, and the water tries to keep going in a straight line, moving away from the Earth, also forming a bulge. In this way the combination of gravity and inertia creates two bulges of water (Ross, D.A. 1995. Introduction to Oceanography. New York, NY: Harper Collins. pp. 236-242).
gir-oft-e kešandi, gir-andâzi-ye ~
Fr.: capture par effet de marées
A process in which two stars remain → bound after their → close encounter, leading to the formation of a → binary system. Tidal capture becomes possible when two stars pass each other so closely (within a few stellar radii) that their → tidal forces are able to absorb the excess energy of → unbound → orbital motion. The process was originally suggested by Fabian et al. (1975) to explain the origin of → low-mass X-ray binary systems observed for the first time in → globular clusters.
jafsari-ye kešandi, jofteš-e
Fr.: couplage par marées
In a system composed of one celestial body orbiting another, the synchronization of the orbital and rotational motions of the two bodies under the action of → tidal forces. For example, Pluto is tidally coupled to its moon Charon. As for the → Earth-Moon system, billions of years from now, the Earth and the Moon will have the same period of rotation, and these will also exactly equal the orbital period of the Moon around the Earth. → tidal friction.