Hexagons are six-sided polygons. The root word hexa means six, indicating the hexagon's characteristic six sides, which sets it apart from other polygons.
Regular hexagons have six sides of equal length and interior angles that add up to 720 degrees. Hexagons don't have to have sides of equal length, though. Any closed shape with six sides is a hexagon. Hexagons that have sides of unequal length can be referred to as arbitrary hexagons. However, in a neat turn, according to Wolfram MathWorld, connecting the centroids of any arbitrary hexagon will result in a regular hexagon with six equal sides.