prime meridian
noun
the meridian running through Greenwich, England, from which longitude east and west is reckoned.
Origin of prime meridian
First recorded in 1860–65
Words nearby prime meridian
prime cost,
prime field,
prime focus,
prime ideal,
prime interest rate,
prime meridian,
prime minister,
prime mover,
prime number,
prime number theorem,
prime of life
British Dictionary definitions for prime meridian
prime meridian
noun
the 0° meridian from which the other meridians or lines of longitude are calculated, usually taken to pass through Greenwich
Scientific definitions for prime meridian
prime meridian
[ prīm ]
The meridian with a longitude of 0°, adopted officially in 1884 as a reference line from which longitude east and west are measured and as a basis for standardized time zones. It passes through Greenwich, England, the site of the Royal Greenwich Observatory, which was founded in 1675 and which closed except as a museum in 1998. The prime meridian, together with its opposite meridian having a longitude of 180°, divide the Earth roughly into the Eastern and Western Hemispheres, with those portions of the British Isles, Europe, and Africa that lie west of the prime meridian, considered for practical purposes as belonging to the Eastern Hemisphere.