Decagon
/ˈdekəɡɑːn/
Definition 1 of 1
Pro Tip 1/3Geometry Term
Commonly used in mathematics to describe a ten-sided polygon, especially in geometry lessons. 
For her homework, she had to calculate the interior angles of a decagon.
Pro Tip 2/3Regular vs. Irregular
A 'regular decagon' has all sides and angles equal, while an 'irregular decagon' does not. 
A stop sign is an example of an irregular octagon, not a decagon.
Pro Tip 3/3Convex Shape
A convex decagon means all points on the interior angles point outward, with no indentations. 
Convex decagons are often used in tiling patterns.