This document discusses homonyms and polysemy. A homonym is a word that is spelled and pronounced the same as another word but has a different meaning. Polysemy refers to a single word having multiple related meanings. The document provides examples of homonyms like "arm" and "flat" and polysemous words like "book" and "milk." It explains that while homonyms have no relationship between meanings, polysemous meanings can be traced etymologically and semantically.