Science, Tech, Math › Science Colloid Definition - Chemistry Glossary Share Flipboard Email Print These tubes contain colloidal mixtures displaying luminescence. nina_piatrouskaya / Getty Images Science Chemistry Chemical Laws Basics Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated September 04, 2019 A colloid is a type of homogeneous mixture in which the dispersed particles do not settle out. The insoluble particles in the mixture are microscopic, with particle sizes between 1 and 1000 nanometers. The mixture may be termed a colloid or a colloidal suspension. The phrase "colloidal solution" is incorrect. Sometimes the term "colloid" only refers to the particles in the mixture and not the entire suspension. Colloids may be translucent due to the Tyndall effect, where light is scattered by particles in the mixture. Examples of Colloids Colloids may be gases, liquids, or solids. Examples of familiar colloids include butter, milk, smoke, fog, ink, and paint. Cytoplasm is another example of a colloid. Source Levine, Ira N. (2001). Physical Chemistry (5th ed.). Boston: McGraw-Hill. p. 955. ISBN 978-0-07-231808-1.