Better yet why not call a quadrilateral a
qaudriangle? Or maybe
Quadrigon?
A five sided object is can also be called a
Pentalateral can also be a
Pentangle?
How does maybe a
Triagigon or Trigon sound for triangle
?
Hexagon can also be a Hexiangle or Hexerlateral!
The famous Octagon, American Stop, Sign can also be called an Octiangle or a Octalateral!
There is the theoretical closed
Biangle that only exists in high dimensions or rather the
Bilateral. Closed Biangles shapes don't exist in our universe, except for maybe Pac-Man's tunnel.
Maybe Diangle, Diagon, or Dilateral is better?
Likewise there is the invisible
Monoangle which can be called a
Monogon or
Monolateral, and you have to be in "God-Mode" to understand that. Unigon, Unilateral, and Uniangle are additional names for the Monogon. They really do exist, more so than the Great Pumpkin.