Retaining wall?

Was thinking of that - wouldnt it have to be quite high?

It is called a retaining wall

Here are some suggestions:

Very pretty…but …very heavy pieces to pick up and stack…very expensive to have delivered..and requires a talented stone layer to execute properly…mostly used when you have finished roads and are in communities that more residential

It will probably require a crane and operator to lift and place stones that size…but it takes something substantial to deter the slope from sliding when it rains..it looks like you are in a neighborhood where all that may be justified…