- the 0° meridian from which the other meridians or lines of longitude are calculated, usually taken to pass through Greenwich
WordReference Random House Learner's Dictionary of American English © 2026
ˈprime meˈrid•i•an, n. [countable;
usually: the + ~]
WordReference Random House Unabridged Dictionary of American English © 2026usually: the + ~]
- Geographythe meridian running through Greenwich, England, from which longitude east and west is figured.
prime′ merid′ian,
- Geographythe meridian running through Greenwich, England, from which longitude east and west is reckoned.
- 1860–65
Collins Concise English Dictionary © HarperCollins Publishers::
prime meridian n
'prime meridian' also found in these entries (note: many are not synonyms or translations):