Definition:Meridian/Terrestrial
Definition
A (terrestrial) meridian is a semi-great circle on Earth's surface whose endpoints are Earth's poles.
Principal Meridian
A principal meridian is an arbitrary reference meridian of Earth which is used in a given context to determine (terrestrial) longitude.
Usually this is for land surveying.
Prime Meridian
A prime meridian is a terrestrial meridian which is determined by history and circumstance to be the international reference meridian with respect to which terrestrial longitude is defined.
Also defined as
Some sources define a (terrestrial) meridian as be a complete great circle passing through both of Earth's poles.
However, this definition is less convenient, and will not be used on $\mathsf{Pr} \infty \mathsf{fWiki}$.
Also known as
In common parlance, a terrestrial meridian is usually referred to as just a meridian.
The terrestrial descriptor is added so as to distinguish it from a celestial meridian.
Also see
- Results about terrestrial meridians can be found here.
Sources
- 1933: D.M.Y. Sommerville: Analytical Conics (3rd ed.) ... (previous) ... (next): Chapter $\text I$. Coordinates: $2$. Coordinates
- 1976: W.M. Smart: Textbook on Spherical Astronomy (6th ed.) ... (previous) ... (next): Chapter $\text I$. Spherical Trigonometry: $4$. Terrestrial latitude and longitude.
- 2014: Christopher Clapham and James Nicholson: The Concise Oxford Dictionary of Mathematics (5th ed.) ... (previous) ... (next): meridian