Dewey refers to the Dewey Decimal System, a method of organizing library books developed by Melvil Dewey in 1876. This system uses a three-digit number to categorize books by subject, making it easier for people to find what they are looking for. For example, books about history might be assigned numbers in the 900s, while those about science are in the 500s. In addition to the library system, Dewey can also refer to Dewey the Library Cat, a famous feline who lived in a library in Spencer, Iowa. He became beloved by the community and inspired a book about his life, showcasing the special bond between animals and people.