i think hes refering to AAA used in metro 2033/lastlight.
bsaically its advance anti aliasing. that includes ambient occlusion that uses special techniques to reduce blocky edges on things like mesh textures that are semi transparent but in shadow or bright light. especially on wire mesh fences which distort and give unrealistic results if viewed from certain angles.
ambient occlusion is just a method of representing light and shadow to give a more realistic look to 3d environments and the objects in it. it basically increases depth of vision rather than having flat shadows they deepen the further the objects are from the light.
basic image but it gives you all the info you need.
fsaa or basic anti aliasing is done by creating an image x2,x4,x8 times bigger than is displayed on the screen its then compressed in a way that gives the illusion of smoothed edges.
there are different kinds of AA but they all give the same results more or less. smoothed edges