Found 1 definition: prime meridian.

[WORDNET DICTIONARY]

**prime meridian**(n = noun.location) - meridian at zero degree longitude from which east and west are reckoned (usually the Greenwich longitude in England);

is a kind of line of longitude, meridian

has particulars: greenwich meridian

[RELATED WORDS]

greenwich meridian, magnetic meridian, meridian, observer's meridian, prime, prime factor, prime interest rate, prime minister, prime mover, prime number, prime of life, prime quantity, prime time