false easting

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun cartography A value relating to distance east of a standard meridian but with a constant added to make the numbers convenient. For instance, in UTM the value 500,000 is added to the easting from the center of each zone to return a false easting that is never negative (the smallest true easting is approximately -340,000 which set to false easting of 160,000).