Definition:Greenwich Meridian
Definition
The Greenwich meridian is the meridian of Earth which passes through the Royal Observatory in Greenwich, Greater London, England.
Also known as
The Greenwich meridian has also been known as the following at some stage during the course of its history:
- the prime meridian
- the principal meridian
- the standard meridian
and so on.
It has since been superseded as the standard meridian.
Also see
- Results about the Greenwich meridian can be found here.
Historical Note
From $1884$ until $1974$, the Greenwich meridian was used as the prime meridian.
That is, the internationally-recognised $0 \degrees$ reference longitude meridian from which all longitude was defined.
This has since been superseded by the IERS reference meridian, which is based on a different principle.
However, many reference works and textbooks written since $1974$ still refer to the Greenwich meridian as the prime meridian.
Linguistic Note
The place name Greenwich, in the context of the Greenwich meridian, is pronounced something like Gren-itch or Gren-idge.
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.
- 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): meridian: 1.
- 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): meridian: 1.
- 2014: Christopher Clapham and James Nicholson: The Concise Oxford Dictionary of Mathematics (5th ed.) ... (previous) ... (next): prime meridian