Homogenization is the process of making something the same consistency throughout. The homogenization of milk makes the fat particles be evenly distributed, so they don't clump together at the top into a separate layer.
Other food products that are typically put through homogenization include peanut butter and salad dressings. Manufactured products like pharmaceuticals, cosmetics, and paints also go through homogenization. The term is sometimes used more figuratively: Sociologists might refer to the homogenization of culture due to things like the widespread use of social media and dissemination of music, literature, and films around the world, perhaps forming a more uniform global identity. Homogenization comes from the Greek roots homo-, "same," and gene, "kind."