Blend Shader: a shader that is part of a family of related shaders used to texture a terrain entity. It represents a terrain texture in its blended state, two textures that crossfade across each other. The naming convention for a blend shader is <metashadername>_#to#.

Metashader: the identifying name of a group of related shaders used to texture a terrain entity. By way of example, the metashader name used to texture mpterra2 was … mpterra2. Its root shaders had names like mpterra2_0, mpterra2_1, and mpterra2_2. Its blend shaders were named mpterra2_0to1, mpterra2_1to2, and mpterra2_0to2.