The arc or portion of the earth's equator intersected between the meridian of a given place and the prime meridian and expressed either in degrees or in time. (NASA)
James Daniell (compiler), Glossary of Earthquake Terms (shortened list of the most important terms), Earthquake-Report.com, Guam, USA 2011. http://earthquake-report.com/2011/02/15/glossary-o f-earthquake-terms-2/, (ND/ Erthq - Brit) {898}