Meridian is:

• Meridian (astronomy): an imaginary circle perpendicular to the horizon.
• Meridian (geography): either half or a full great circle that connects the Earth's poles.
• Meridian (TCM): an important concept in traditional Chinese medicine.
• Meridian (perimetry, visual field): a polar coordiate system for the visual field.
• The name of some places in the United States of America:
  • Meridian, Idaho
  • Meridian, Mississippi
  • Meridian, New York
  • Meridian, Oklahoma
• Meridian is also a novel by Alice Walker.
• Meridian Broadcasting has been the ITV station for the south of England since 1992.
• Meridian Energy Limited is a New Zealand electricity generation and electricity retailing company.
• Meridian was a comic book published by CrossGen in the early 2000s, and was the name of a city-state in that comic.
• Meridian is the name of a line of business telecommunication products produced and marketed by Nortel Networks.

• Meridian is also a term used by the Public Land Survey System in the United States.
• Meridian is the Capital of Nosgoth in the Legacy of Kain series of video games.
• Meridian is also an online game, Meridian 59 (www.meridian59.com) the first online game to hit, developed by Andrew and Chris Kirmse of Archetype. They finally hit the market in early 1995 and were bought by 3DO Entertainment. The game was bought by Near Death Studios from 3DO in 2001 after 3DO shut down all of their servers and has been running since then. The game also has a very popular fansite at www.gilcon.net/meridian.
• Meridian is the name of a music program, made to play a few different formats of video game music (NSF, GBS, GYM, and SPC). The website is http://meridian.overclocked.org/.