geocentric terrestrial reference system (GTRS)
a system of geocentric space-time coordinates within the framework of General Relativity, co-rotating with the Earth, and related to the GCRS by a spatial rotation which takes into account the Earth orientation parameters. It was adopted by IUGG 2007 Resolution 2. It replaces the previously defined Conventional Terrestrial Reference System.
Source: 
Glossary (PDF, 237KB) of the IERS Conventions (2010)
Original Source: IAU 2006 NFA Glossary
