Nonagon
/ˈnɑːnəɡɑːn/
Definition 1 of 1
Pro Tip 1/3Geometry Term
Nonagon is primarily used in geometry to discuss shapes. 
On our geometry quiz, we had to calculate the area of a nonagon.
Pro Tip 2/3Regular vs. Irregular
A 'regular nonagon' has sides of equal length, unlike an 'irregular nonagon'. 
The puzzle piece looked like an irregular nonagon.
Pro Tip 3/3Angles Sum
The sum of interior angles in any nonagon is 1260 degrees. 
The teacher explained that regardless of its shape, every nonagon's angles sum to 1260 degrees.