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

A 4th → rank tensor that characterizes the deviation of the geometry of space from the Euclidean type. The curvature tensor R^λ_μνκ is defined through the → Christoffel symbols Γ^λ_μν as follows: R^λ_μνκ = (∂Γ^λ_μκ)/(∂x^ν) - (∂Γ^λ_μν)/(∂x^κ) + Γ^η_μκΓ^λ_ην - Γ^η_μνΓ^λ_ηκ.

→ Riemannian geometry; → curvature; → tensor.

An alternative to the standard → general relativity of gravity that contains not only the → tensor field (or → metric), but also a → scalar field. In this formalism, the → gravitational constant is considered to vary over time. As a consequence, the measured strength of the gravitational interaction is a function of time. Same as → Jordan-Brans-Dicke theory.

→ scalar; → tensor; → theory.

1) Grammar: A grammatical unit of one or more words that expresses an independent statement, question, request, command, exclamation, etc., and that typically has a subject as well as a predicate, as in John is here. or Is John here? (Dictionary.com).
2) Law: An authoritative decision; a judicial judgment or decree, especially the judicial determination of the punishment to be inflicted on a convicted criminal: Knowledgeable sources say that the judge will announce the sentence early next week (Dictionary.com).

M.E., from O.Fr. sentence "judgment, decision; statement of authority," from L. sententia "thought, opinion; judgment," also "a thought expressed," from sentientem, p.p. of sentire "be of opinion, feel, perceive."

Sahân, related to soxan, → speech and pâsox, → response; Mid.Pers saxwan "speech, word;" O.Pers. θaⁿh- "to declare, say;" Av. səngh- (sanh-) "to declare;" Proto-Ir. *sanh- "to declare, explain;" cf. Skt. śams- "to praise, recite;" L. censere "to estimate, think; decide;" PIE *kens- "to announce, proclaim" (Cheung 2007).

Pertaining to or of the nature of a → sentence.

From L. sententi(a), → sentence, + → -al.

Same as → propositional logic.

→ sentential; → logic.

A tensor that is the negative of its → transpose. For example, a second-order covariant tensor A_jk if its components satisfy the equality: A_jk = - A_kj. Also called antisymmetric tensor.

→ skew; → symmetric; → tensor.

Tânsor, → tensor; pâd-, → anti-; hamâmun, → symmetric.

The average → sound power passing through a unit area perpendicular to the direction that the sound is traveling. It is usually expressed in watts per square meter.

→ sound; → level.

The expression of sound intensity in decibel units. The sound intensity level (L_I), in decibels, is computed as: L_I = 10 log (I/I₀), where I is the measured sound intensity and I₀ is the reference intensity (1 x 10 ^-12 watt per square meter).

→ sound; → intensity; → level.

A measure of the amount of radiation received per unit solid angle per unit time per unit area normally from an element of surface.

→ specific; → intensity.

To be opposite and delimit the extent of an angle or side of a geometric figure.

From L. subtendere "to stretch beneath," from → sub- + tendere "to stretch," cognate with Pers. târ "string," tanidan "to weave," as below.

Zirtânidan from zir-, → sub-, + tânidan from tân "thread, warp of a web," tâl "thread" (Borujerdi dialect), târ "thread, warp, string," related to tur "net, fishing net, snare," from tanidan, tan- "to spin, twist, weave;" Mid.Pers. tanitan; Av. tan- "to stretch, extend;" cf. Skt. tan- to stretch, extend;" tanoti "stretches," tántra- "warp; essence, main point;" Gk. teinein "to stretch, pull tight;" L. tendere "to stretch, as above; Lith. tiñklas "net, fishing net, snare," Latv. tikls "net;" PIE base *ten- "to stretch."

An angle whose two sides pass through the endpoints of an arc.

Subtended p.p. of → subtend; → angle.

The inward → attraction of the → molecules at the → surface of a → liquid. The reason is that the molecules at the surface do not have other like molecules on all sides of them and consequently they cohere more strongly to those directly associated with them on the surface. Also called surface energy and capillary forces.

→ surface; → tension.

A tensor that is → invariant under any → permutation of its indices (→ index). In other words, a tensor that equals its → transpose. For example, a second-order → covariant tensor A_jk if its components satisfy the equality: A_jk = A_kj.

→ symmetric; → tensor.

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.

A method of calculation in higher mathematics based on the properties of tensors.

→ tensor; → analysis.