A hexadecagon is a polygon with 16 sides and 16 angles. It is also commonly known as a 16-gon. Synonyms for this word include "sixteen-sided polygon," "decakaidecagon," "heptadecagon," and "icosakaipentagon." The term "decakaidecagon" is derived from the Greek words for "10" and "15," while "heptadecagon" is from the Greek words for "seven" and "10." "Icosakaipentagon," on the other hand, combines the Greek words for "20" and "15." Regardless of the term used, a hexadecagon is a unique and interesting shape in the world of geometry.