Polymers are molecules that are made from many repeating units. A decent analogy for a polymer is a train. Trains are made up of many, many train cars, and you get a train when you link them together. Polymers are made from many, many small chemical units (called "monomers"), and you get a polymer when you link them together with chemical bonds. The word "polymer" comes from two greek words: "polu" meaning "many" and "meros" which rough means "a part". Together "poly-mer" means "many parts" which describes polymers pretty well. The "mono-mer" is then "one part", where "mono" means one. Polymers are everywhere in your daily life including plastics, glues, shampoos, and many more things.