Anisotropic filtering
Texture filtering that samples along the direction the surface slants away in, keeping floors and roads that recede toward the horizon sharp instead of blurred.
Ordinary bilinear and trilinear filtering assume a pixel covers a roughly square patch of the texture. At grazing angles — a road stretching off toward the horizon — the covered patch is instead long and thin, and a square mipmap sample comes out far too blurry.
Anisotropic filtering (usually written AF, graded 2× to 16×) instead takes several samples stretched along that direction and weights them together. The result is noticeably sharper textures into the distance at a relatively modest cost, and it has been a standard graphics-card feature since the early 2000s. It leans on the UV mapping that decides how the texture lies on the surface.