What does the term Anti Aliasing mean in video games?
Anti-aliasing, or AA for short, is a technique that smooths out jagged edges on objects in a rendered image. This helps to create a more realistic look and feel by making it appear as if an object has been drawn with higher resolution than what was actually used when generating the final picture.

AA works by interpolating between sampled positions (in this case, from vertexes) during rendering of surfaces to generate smoother areas. By smoothing over all positions at once instead of only individual ones, there's less visible flicker or other artifacts where previously sharp transitions occur. The effectiveness of anti-aliasing can vary depending on a number of factors like scene complexity, GPU hardware, and artistic intent, but generally speaking AA is most useful for adding detail while preserving appearance fidelity.