A wind-up toy is a mechanical or clockwork toy that is powered by a spring mechanism. Some synonyms for the term wind-up toy are clockwork toy, mechanical toy, spring-powered toy and windable toy. These kinds of toys were especially popular in the 19th and early 20th centuries but continue to be manufactured and enjoyed today. They come in a wide variety of shapes and sizes, from classic tin robots to novelty animals and vehicles. Despite their simple mechanisms, wind-up toys can provide hours of entertainment for children and adults alike, and make for great collector's items for those interested in vintage toys.