An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



Number of Results: 11 Search : triangle
congruent triangles
  سه‌برهای ِ دمساز   
sebarhâ-ye damsâz

Fr.: triangles congrus   

Two triangles when all corresponding sides and interior angles have the same measure. The triangles will have the same shape and size, but one may be a mirror image of the other.

congruent; → triangle.

equilateral triangle
  سه‌بر ِ سه-پهلو-برابر   
sebar-e sé-pahlu-barâbar (#)

Fr.: triangle équilatéral   

A triangle having three equal sides.

equi-, → lateral, → triangle.

Sé-pahlu-barâbar, from , → three, pahlu, → side, barâbar, → equal.

isosceles triangle
  سه‌بر ِ دو-پهلو-برابر   
sebar-e do-pahlu-barâbar (#)

Fr.: triangle équilatéral   

A triangle having two sides equal.

From L.L. isosceles, from Gk. isoskeles "with equal legs; that can be divided into two equal parts," from isos "equal, identical," → iso-, + skelos "leg."

Sebar, → triangle, do-pahlu-baraabar, from do, → two, pahlu, → side, barâbar, → equal.

Pascal's triangle
  سه‌بر ِ پاسکال   
sebar-e Pascal

Fr.: triangle de Pascal   

An array of numbers in the shape of a triangle, having a 1 at the top and also at the ends of each row. Each number is obtained by summing the two adjacent numbers to it in the preceding row. Each row is a set of → binomial coefficients. In the expansion of (x + y)n, the coefficients of x and y are given by the n-th row of Pascal's traingle.

pascal; → triangle.

Reuleaux triangle
  سه‌بر ِ رولو   
sebar-e Reuleaux

Fr.: triangle de Reuleaux   

A shape of constant width created using an equilateral triangle and three similar circles. The equilateral triangle lies in the first circle with a vertex coinciding with the center of the circle and the sides equal to the circle radius. The centers of the two other circles are located at the two other vertices. The Reuleaux triangle is the intersection of the three circles.

Named after Franz Reuleaux (1829-1905), a German engineer, specialist of analysis and design of mechines; → triangle.

right triangle
  سه‌بر ِ راست   
sebar-e râst (#)

Fr.: triangle droit   

A triangle one of whose angles is a → right angle.

right; → triangle.

scalene triangle
  سه‌بر ِ ناجور-پهلو   
sebar-e nâjur-pahlu

Fr.: triangle scalène   

A triangle no two sides of which are equal.

From L.L. scalenus, from Gk. skalenos "uneven, unequal, rough," from skallein "chop, hoe," related to skolios "crooked," from PIE base *(s)qel- "crooked, curved, bent;" → triangle.

Sebar, → triangle; nâjur-pahlu "dissimilar sides," from nâjur "dissimilar, ill-matched" + pahlu "side, flank" (Mid.Pers. pahlug "side, rib," Av. pərəsu- "rib," Ossetic fars "side, flank," cf. Skt. párśu- "rib," Lith. piršys (pl.) "horse breast").

spherical triangle
  سه‌بر ِ کُره‌ای   
sebar-e kore-yi

Fr.: triangle sphérique   

A triangle drawn on the → surface of a → sphere. A spherical triangle, like a plane triangle, may be right, obtuse, acute, equilateral, isosceles, or scalene. The sum of the angles of a spherical triangle is greater than 180° (π) and less than 540° (3π). See also → spherical excess.

spherical; → triangle.

summer triangle
  سه‌بر ِ تابستانی   
sebar-e tâbestâni

Fr.: triangle d'été   

The triangular shape formed by the three bright stars → Altair, → Deneb, and → Vega on the northern hemisphere's → celestial sphere, particularly visible during the summer months.

summer; → triangle.

  سه‌بر، سه‌گوش   
sebar (#), seguš (#)

Fr.: triangle   

The plane figure formed by three lines intersecting in pairs at three points; a three-sided → polygon. → equilateral triangle, → isosceles triangle, → scalene triangle.

M.E., from O.Fr. triangle, from L. triangulum "triangle," from neuter of adj. triangulus "three-cornered," from tri-, → three, + angulus "corner," → angle.

Sebar "three-sided," from , → three, + + bar "side; breadth; breast," variant var (Mid.Pers. var "breast;" Av. vouru "wide, broad, extended" (vourucašāni- "looking far"), related to varah- "breast;" cf. Skt. urú- "wide, broad," úras- "breast;" Gk. eurus "wide, broad;" PIE base uer-, ueru-s"wide, broad").
Seguš "three-cornered," from , → three, + guš "corner, angle," Mid.Pers. gošak "corner."

triangle inequality
  ناهموگی ِ سه‌بری   
nâhamugi-ye sebari

Fr.: inégalité triangulaire   

1) A theorem according to which any side of a triangle is always shorter than the sum of the other two sides.
2) The third requirement for a → distance function describing a → metric space.

triangle; → inequality.