Of course a retaining wall will stabilize a slope, but it stands at 90 degrees and chops off the bottom part of the slope. From your description, it seems that you're looking for some form of cladding that covers the entire slope. I was able to find several examples of 'rock veneer'. (I had no luck with 'stone veneer', 'stone cladding', or 'stone sheet(ing)' in the context of slope stabilization.)

If it's not the perfect term, at least it's accurately descriptive.

www.nps.gov/features/glac/gtsr/.../e-ch3.pdf
U.S. National Park Service
Drainage, slope stability, retaining walls, guardwalls, and roadway pavement ..... cally stabilizing the earth (MSE) and reducing or eliminating the load on the .... **Finish the remaining rock veneer work** in the same fashion as it was started; or.

www.mdt.mt.gov/.../pesc_manual...
Montana Department of Transportation
Steep Fill or Cut Slopes Slope Soil Stabilization. Section A9.0 ...... **Rock veneer** is appropriate in areas where the finished slope is composed of highly erodible ...

www.nab.usace.army.mil/.../PN%...
United States Army Corps of Engineers
Apr 2, 2014 - 0029, on the existing alignment, because of an underlying slope ... stream bank, **a 10-foot rock veneer will be constructed** with R-8 rock chocked with native ... are due to the placement of fill associated with the stabilization.

The following definition refers to a natural formation, but the other ones are man-made.

en.wikipedia.org/wiki/Rock_veneer
Wikipedia
A rock veneer is a geomorphic formation in which rock fragments (clasts) of gravel or cobble size form a thin cover over a surface or hillslope. Rock veneers are ...