UTM (Universal Transverse Mercator)
Computers eat it for breakfast because it reads like Cartesian coordinates.

 from http://geokov.com/education/utm.aspx

Grid zones are 6 degrees wide with a central meridian
They start at 180 degrees west of Greenwich and increase in number going east.  In Lexington, we’re in grid zone 17, which has 81 degrees W as the central meridian. Usually, only one grid zone used even for areas near the boundary of a grid zone. See the orthophoto map from North Carolina in R:\courses\GEOL260.
US Grid Zones and World Grid zones

ArcGIS Pro: For UTM / Geographic comparison,

  • See the projections_and_datums layout from the Demo\intro\introPro project
  • make a new map (in a new tab)
  • copy the “Lex_quad.tif” from the existing layout.
  • Change the map projection from one grid zone to another (e.g., zone 17 to zone 18, then to zone 10 !). Note that the data stays in its coordinate system, but it is projected on the fly into some other coordinate system.