Diameteren

Diameteren is a term used in Scandinavian languages to denote the diameter of a circle or sphere, and can appear as the definite form of the noun diameter (for example, in Norwegian diameteren; Swedish diametern; Danish diameteren). As a proper noun, Diameteren may also appear in titles or names, though it is not standard English usage.

In geometry, the diameter of a circle is the longest chord, a line that passes through the center and connects two points on the circle. The diameter D is twice the radius r: D = 2r. It relates to other circle parameters by A = πr^2 = (π/4)D^2 for the area and C = πD for the circumference.

Diameter is used across science and engineering to specify sizes of wheels, pipes, gears, and bore diameters, as well as in architectural and manufacturing contexts. It can be measured directly by determining the distance across the circle through the center, or inferred from chords, imaging methods, or calibrated instruments such as calipers.

Etymology and usage: the word diameter comes from Greek dia ‘through’ and metron ‘measure’. In Swedish, Danish, and Norwegian, the noun forms differ in spelling and the definite form in each language corresponds to the neutral singular; the English form does not use the definite suffix in ordinary text. When capitalized as Diameteren, it is typically encountered as a title or proper noun rather than a common geometric term.

See also: diameter, radius, circumference, circle.