Colloids exist in eight different forms based on the state of the "dispersed phase" (the particles) and the "dispersion medium" (the substance they are in): Colloid - an overview | ScienceDirect Topics
Colloid and interface science is the study of mixtures where one substance is dispersed throughout another at a microscopic level, specifically with particles ranging from . This field is often called the "bridge to nanoscience" because it focuses on the unique behaviors that occur when materials have a massive surface area relative to their volume. The World of Colloids