When used with respect to survey ["control"], order is a specification of the accuracy and precision of the measurements that were made. The ["NGS"] has standards that must be met for the different orders of accuracy.

On an NGS datasheet, one of the lines will say "HORZ ORDER" (geocaching datasheets do not have this specification line). The levels of order and their accuracy are:

 GPS Standards Horz. Order Definition AA a relative accuracy of 3 mm +/- 1:100,000,000 relative to other AA-order stations. A a relative accuracy of 5 mm +/- 1:10,000,000 relative to other A-order stations. B a relative accuracy of 8 mm +/- 1: 1,000,000 relative to other A- and B-order stations.
 Classical standards Horz. Order Definition First 1: 100,000 relative to other stations of the same order. Second-order, class I 1: 50,000 relative to other stations of the same order. Second-order, class II 1: 20,000 relative to other stations of the same order. Third-order, class I 1:10,000 relative to other stations of the same order. Third-order, class II 1:5,000 relative to other stations of the same order.

The classical relative accuracy specifies a distance tolerance. For instance, if two first-order points are separated by 10km, then the distance between them will be accurate to 10 cm, in principle. To estimate the absolute accuracy of a position, a resonable estimate for a "classical" station would be based on the distance from the station to the nearest CORS, HARN, or FBN station that existed at the time of adjustment within the same state as the station. For instance, here is a portion of a datasheet:

LY2625  DESIGNATION -  BEVANS
LY2625  PID         -  LY2625
LY2625  STATE/COUNTY-  NJ/SUSSEX
LY2625  USGS QUAD   -  CULVERS GAP (1997)
LY2625
LY2625                         *CURRENT SURVEY CONTROL
LY2625  ___________________________________________________________________