Megatexture
A megatexture is a texture which is higher resolution than normal, but instead of using the increased resolution for increased fidelity, the texture scale is kept the same as (or lower than) a regular texture and the increased resolution is instead used for reducing tiling repetition on large surfaces. Megatextures often may be used in conjunction with a detail texture, which adds back detail that may be lost from stretching a texture across a large surface.
The Counter-Strike: Global Offensive Danger Zone map dz_sirocco uses two blended megatextures (one 1024x1024 and one 2048x2048) which cover the entire map, in conjunction with denser detail textures.