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

1) To become smaller, shorter, tighter, as a metal when cooled.
2) To reduce to smaller size by or as if by squeezing or forcing together, e.g. contract a muscle.
→ contraction, → gravitational contraction, → Kelvin-Helmholtz contraction, → length contraction, → Lorentz contraction, → vena contracta.

From M.E., from O.F., from L. contractus, p.p. of contrahere "to draw together," from → com- "together" + trahere "to draw."

Terengidan, variant taranjidan [Dehxodâ] "to contract, become rough and hard, to be squeezed, compressed," Borujerdi terengessa "cramped, tightly dressed," Malâyeri terengidan "to be tightly dressed, cramped in a garment," related to tarang "horse girth, a strap for fastening a load," Proto-Iranian *trng- "to pull tight, squeeze, compress;" PIE base *strenk- "to pull tight, twist; tight, narrow" (cf. L. stringere "to bind or draw tight;" Gk. strangein "to twist;" Lith. stregti "to congeal;" O.E. streccian "to stretch," streng "string;" Ger. stramm, Du. stram "stiff").

An act or instance of contracting; the quality or state of being contracted.
→ gravitational contraction, → Kelvin-Helmholtz contraction, → length contraction, → Lorentz contraction.

Verbal noun of → contract.

Decrease in the volume of an astronomical object under the action of a dominant, central gravitational force.

→ gravitational; → contraction.

The contraction of a volume of gas under its → gravity, accompanied by the → radiation of the lost → potential energy as → heat.

After the Scottish physicist William Thomson, also known as Lord Kelvin (1824-1907) and the German physicist and physician Hermann Ludwig Ferdinand von Helmholtz (1821-1894), who made important contributions to the thermodynamics of gaseous systems; → contraction.

Same as → Lorentz contraction.

→ length; → contraction.

The decrease in the length of a body moving in the direction of its length as measured by an observer situated in that direction. The shortening factor is [1 - (v/c)²]^1/2, where v is the relative velocity and c light speed.

→ Lorentz; → contraction.

An operation of tensor algebra that is obtained by setting unlike indices equal and summing according to a summation convention.

→ contraction; → tensor.

The location in a → fluid stream where the → cross section of the → stream is at a minimum, and fluid velocity is the highest, such as in the case of a → jet issuing out of a → nozzle.

L. vena "channel;" contracta, "contracted," → contract.

Šâre-gozar "fluid passage," → fluid; → passage, terengidé, → contracted.