Definition of pentagon

The word "pentagon" has its roots in Greek and Latin. The prefix "pente" comes from the Greek word πέντε (pente), meaning "five", and the suffix "-gon" is derived from the Greek word γωνία (gonia), meaning "angle" or "corner". In Latin, the term "quinquangulus" was used to describe a five-sided shape, and it was later adapted into Middle English as "pentagon". The modern English word "pentagon" was first used in the 16th century to describe a five-sided polygon. The term was initially used to describe geometric shapes, but it eventually came to be used to describe the United States Department of Defense's headquarters building, which was designed in the shape of a pentagon. Today, the word "pentagon" is used to describe not only geometric shapes but also the government agency and its various branches.