Dictionary > Triangle

Triangle

triangle
1. (Science: geometry) A figure bounded by three lines, and containing three angles.
A triangle is either plane, spherical, or curvilinear, according as its sides are straight lines, or arcs of great circles of a sphere, or any curved lines whatever. A plane triangle is designated as scalene, isosceles, or equilateral, according as it has no two sides equal, two sides equal, or all sides equal; and also as right-angled, or oblique-angled, according as it has one right angle, or none; and oblique-angled triangle is either acute-angled, or obtuse-angled, according as all the angles are acute, or one of them obtuse. The terms scalene, isosceles, equilateral, right-angled, acute-angled, and obtuse-angled, are applied to spherical triangles in the same sense as to plane triangles.
2. An instrument of percussion, usually made of a rod of steel, bent into the form of a triangle, open at one angle, and sounded by being struck with a small metallic rod.
3. A draughtsman’s square in the form of a right-angled triangle.
4. A kind of frame formed of three poles stuck in the ground and united at the top, to which soldiers were bound when undergoing corporal punishment, now disused.
5. (Science: astronomy) A small constellation situated between aries and andromeda. A small constellation near the south pole, containing three bright stars.
(Science: zoology) Triangle spider, a small American spider (Hyptiotes Americanus) of the family Ciniflonidae, living among the dead branches of evergreen trees. It constructs a triangular web, or net, usually composed of four radii crossed by a double elastic fibre. The spider holds the thread at the apex of the web and stretches it tight, but lets go and springs the net when an insect comes in contact with it.
Origin: L. Triangulum, fr. Triangulus triangular; tri- (see Tri-) – angulus angle: cf. F. Triangle. See Angle a corner.


You will also like...

Cell Biology
Cell Biology

The cell is defined as the fundamental, functional unit of life. Some organisms are comprised of only one cell whereas o..

Still Water Community Plants
Still Water Community Plants

This tutorial looks at the adaptations of freshwater plants for them to thrive in still water habitats. Familiarize your..

An artistic depiction of a human embryo
Growth and Development of a Human Baby

Upon fertilization, a zygote forms and develops into an embryo. This tutorial elaborates on the growth and development f..

Peppered moth ("Biston betularia") melanic and light form
Examples of Natural Selection

Darwin's Finches are an example of natural selection in action. They are an excellent example of the way species' gene p..

Homo Species
The Homo Species

The evolution of the species of the genus "Homo" led to the emergence of modern humans. Find out more about human evolut..

IQ, Creativity and Learning
IQ, Creativity and Learning

Human intelligence provided the means to utilize abstract ideas and implement reasoning. This tutorial takes a further l..