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

A brittle metallic element usually found in combination with → gold and other → metals, used to → alloy stainless → steel and → lead, and, as bismuth telluride, in thermoelectric devices; symbol Te. → Atomic number 52; → atomic weight 127.60; → melting point 450°C; → boiling point 990°C; → specific gravity 6.24 at 20°C. It was discovered by the Roumanian mine director Franz Joseph Muller von Reichenstein in 1782 and overlooked for sixteen years until it was first isolated by German chemist Martin-Heinrich Klaproth in 1798. The Hungarian chemist Paul Kitaibel independently discovered tellurium in 1789, prior to Klaproth's work but after von Reichenstein.

From L. tellur-, from tellus "earth" + -ium a L. suffix occurring in the name of some chemical elements.

A → periodic comet that is the progenitor of the → Leonids meteor shower. It has a period of 33 years, a → perihelion of 0.982 → astronomical units, an → eccentricity of 0.904, and an → inclination of 162.7°. It was first discovered in 1865 though its past appearances have been traced back to 1366. Tempel-Tuttle is estimated to have a nucleus of radius 1.8 km and a mass of 1.2 × 10¹³ kg. Also designated 55P/Tempel-Tuttle.

Named after the German astronomer Ernst Wilhelm Tempel (1821-1889) and the American astronomer Horace Parnell Tuttle (1837-1923), who independently discovered the comet on December 19, 1865 and January 6, 1866 respectively.

A physical quantity characterizing the mean random motion of molecules in a physical body. In other words, a measure of the average kinetic energy of the particles of a system.

From L. temperatura "a tempering, moderation," from temperatus, p.p. of temperare "to moderate, to mix." Sense of "degree of heat or cold" first recorded 1670 (Boyle), from L. temperatura, used in this sense by Galileo.

Damâ, from dam "breath of an owen; bellows; smoke; air," also "moment, time," from Mid./Mod.Pers. damidan "to blow, breathe;" Av. dāδmainya- "blowing up;" cf. Skt. dahm- "to blow," dhámati "blows;" Gk. themeros "austere, dark-looking;" Lith. dumti "to blow;" PIE dhem-/dhemə- "to smoke, to blow."

Cosmology: Minute temperature variations of the cosmic microwave background radiation.

→ temperature; → anisotropy.

A physical quantity that describes the rate of change of temperature with displacement in a given direction from a given reference point. Same as → thermal gradient.

→ temperature; → gradient.

Meteo.: A reversal in the normal temperature decrease, the temperature rising with increased elevation in the atmosphere instead of falling. A layer in which temperature increases with altitude.

→ temperature; → inversion.

An elementary unit of time defined as the duration which is necessary for light to travel a distance equal to the classical radius of an electron. Thus, one tempon (τ) is equal to (e²/mc²)(1/c)≅ 10^-23 seconds.

From tamp, from L. tempus "time" + → -on.

1) Of or pertaining to time.
2) Pertaining to or concerned with the present life or this world; worldly.
3) Enduring for a time only; → temporary; transitory; → transient (opposed to eternal).
4) Secular, lay, or civil, as opposed to ecclesiastical.
5) Grammar: Of, pertaining to, or expressing time.

M.E., from O.Fr., from L. temporalis "of a time, but for a time, temporary," from tempus (genitive temporis) "time, season, proper time or season," of unknown origin.

Tâmeni, from tâmen, → time.

A measure of the correlation between the phases of an → electromagnetic wave at different points along the direction of propagation. Temporal coherence indicates to what extent a source is monochromatic. Imagine a source emitting waves with wavelength λ ± Δλ. Waves with wavelength λ and λ + Δλ, which at some point in space constructively interfere, will no longer constructively interfere after some path length l_c = λ²/(2πΔλ); l_c is called the → coherence length.

→ temporal; → coherence.

A unit of time used in the Roman and Ottoman empires that divided the day from sunrise to sunset into 12 equal numbers of hours, resulting in long summer hours and short winter hours.

M.E., from O.Fr. temporal, from L. temporalis "of time, temporary," from tempus (genitive temporis) "time, season, proper time or season," → time; → hour.

Sâ'at→ hour; fasli, of or pertaining to fasl→ season.

The measure of the ability of an observing system to clearly separate events in time. In other words, the shortest time interval that can be determined between two different events.

→ temporal hour; → resolution.

Temporal character or nature.

→ temporal; → -ity.

Lasting, existing, serving, or effective for a time only; not permanent.

From L. temporarius "according to circumstances, of seasonal character, lasting a short time," from tempus (genitive temporis) "time, season."

Tâmenvâr, from tâmen "time", → temporal, + -vâr suffix denoting suiting, befitting, resembling, in the manner of.

To be indecisive or evasive to gain time or delay acting (Dictionary.com).

From M.Fr. temporiser "to pass one's time, wait one's time," from M.L. temporizare "to pass time," from L. tempus (genitive temporis), → temporal.

Tâmenidan from tâmen "time," → temporal, + -idan, → -ize.

A cardinal number, nine plus one.

M.E. ten(e), tenn(e), O.E. ten(e), tien(e); from P.Gmc. *tekhan (cf. O.S. tehan, O.N. tiu, Dan. ti, Du. tien, O.H.G. zehan, Ger. zehn "ten"), cognate with Pers. dah, as below.

Dah, from Mid.Pers. dah "ten;" Av. dasa "ten;" cf. Skt. dáśa- "ten;" Gk. deka "ten;" L. decem "ten;" O.Ir. deich; Lith. dešimtis "ten;" PIE base *dekm.

Stretched tight, as a cord, fiber, etc.; drawn taut; rigid.

From L. tensus, p.p. of tendere "to stretch," → tension.

Tanu "stretched, strained," from tan + -u suffix of excess. The first element tan, from tanidan "to spin, twist, weave" (Mid.Pers. tanitan; Av. tan- to stretch, extend;" cf. Skt. tan- to spin, stretch;" tanoti "stretches," tantram "loom;" Gk. teinein "to stretch, pull tight;" L. tendere "to stretch;" PIE base *ten- "to stretch"), Pers. târ "string," tân "thread," tur "fishing net, net, snare," and tâl "thread" (Borujerdi dialect) belong to this family; variants tanta "cobweb," tanadu, tafen, kartané, kârtané, kâtené, Pashtu tanistah "cobweb;" cf. Skt. tantu- "cobweb, thread, string").

Of or pertaining to → tension.

From M.L. tensilis "capable of being stretched," from L. tensus, p.p. of tendere "to stretch," → tension.

Taneši, related to taneš, → tension.

The force tending to stretch (or produce tension in) an object

→ tensile; → force.

General: The act of stretching or straining; the state of being stretched or strained.
Mechanics: The longitudinal deformation of an elastic body that results in its elongation.
Electricity: Voltage or potential; electromotive force.

M.E., from M.Fr. tension, from L. tensionem (nominative tensio) "a stretching," from tensus, p.p. of tendere "to stretch," cognate with Pers. taneš, as below.

Taneš, verbal noun from tanidan "to spin, twist, weave;" Mid.Pers. tanitan; Av. tan- to stretch, extend;" cf. Skt. tan- to spin, stretch;" tanoti "stretches," tantram "loom;" Gk. teinein "to stretch, pull tight;" L. tendere "to stretch;" PIE base *ten- "to stretch"), Pers. târ "string," tân "thread," tur "fishing net, net, snare," and tâl "thread" (Borujerdi dialect) belong to this family; variants tanta "cobweb," tanadu, tafen, kartané, kârtané, kâtené, Pashtu tanistah "cobweb;" cf. Skt. tantu- "cobweb, thread, string."

A system of numbers or functions where components obey a certain law of transformation when the variables undergo a linear transformation. A tensor may consist of a single number, in which case it is referred to as a tensor of order zero, or simply a → scalar. The tensor of order one represents a → vector. Similarly there will be tensors of order two, three, and so on.
See also:
→ absolute tensor, → calculus of tensors, → contravariant tensor, → covariant tensor, → Einstein tensor, → energy-momentum tensor, → metric tensor, → order of a tensor, → relative tensor, → Ricci tensor, → Riemann curvature tensor, → scalar-tensor theory, → skew-symmetric tensor, → symmetric tensor, → tensor analysis, → tensor contraction, → tensor density, → tensor field, → tensor perturbation, → tensor rank, → tensor-vector-scalar (TeVeS) theory, → weight of a tensor.

Agent noun of tense (v.) → tension.