triangulation

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A surveying technique in which a region is divided into a series of triangular elements based on a line of known length so that accurate measurements of distances and directions may be made by the application of trigonometry.
2. n. The network of triangles so laid out.
3. n. The location of an unknown point, as in navigation, by the formation of a triangle having the unknown point and two known points as the vertices.

Century Dictionary and Cyclopedia

1. n. A making triangular; formation into triangles.
2. n. The operation and immediate result of measuring (ordinarily with a theodolite) the angles of a network of triangles laid out on the earth's surface by marking their vertices. The triangulation usually proceeds from a base-line, the measurement of which is necessary, though no part of the triangulation proper. The geographical positions of the extremities of this base having been ascertained, and the triangulation, or operation of measuring the angles, having been completed, by trigonometrical calculations called the reductiion of the triangulation (commonly involving a process of distributing the errors by least squares, called the adjustment of the triangulation) the geographical positions of all the other vertices are calculated, assuming the figure of the earth to be known. By the combination of the triangulations of different countries tho figure of the earth is ascertained. See cut under base-line.

Wiktionary

1. n. uncountable A technique in surveying in which distances and directions are estimated from an accurately measured baseline and the principles of trigonometry
2. n. countable The network of triangles, so obtained, that are the basis of a map or chart
3. n. uncountable In navigation or seismology, a process by which an unknown location is found using three known distances from known locations.
4. n. chess A delaying move in which the king moves in a triangular path in order to force the advance of a pawn.
5. n. qualitative research The use of three (or more) researchers to interview the same people or to evaluate the same evidence to reduce the impact of individual bias.

GNU Webster's 1913

1. n. (Surv.) The series or network of triangles into which the face of a country, or any portion of it, is divided in a trigonometrical survey; the operation of measuring the elements necessary to determine the triangles into which the country to be surveyed is supposed to be divided, and thus to fix the positions and distances of the several points connected by them.

WordNet 3.0

1. n. a method of surveying; the area is divided into triangles and the length of one side and its angles with the other two are measured, then the lengths of the other sides can be calculated
2. n. a trigonometric method of determining the position of a fixed point from the angles to it from two fixed points a known distance apart; useful in navigation