noun
meridian at zero degree longitude from which east and west are reckoned (usually the Greenwich longitude in England)
• Hypernyms: ↑meridian, ↑line of longitude
• Instance Hyponyms: ↑Greenwich Meridian
* * *
noun
the prime meridian
: an imaginary line that runs from the North Pole to the South Pole through Greenwich, England
Useful english dictionary. 2012.