In Structural Geology, what is the "primative"?

Answer 1

Primitive (note spelling in case you want to search more). The perimeter of the stereonet. The perimeter indicates compass directions. Commonly divided into 360 degrees at 2 degree increments.
Primitive circle is the projected location of the great circle separating the near and far hemispheres (90 degrees from the point of tangency).http://www.uwgb.edu/dutchs/structge/sphproj.htm