A heptadecagon is a geometrical shape that consists of 17 straight sides and 17 angles. It is a convex polygon because all of its angles point outwards. The word heptadecagon is derived from the Greek words "hepta" meaning seven and "deka" meaning ten, which when combined refer to the number 17. A heptadecagon is a very rare geometric shape, and it is not often encountered in everyday life. However, it is an important concept in mathematics, and it has applications in various fields including physics, architecture, and computer science.