I'm asking this question for William Blackwell, who has yet to get connected but hopes to do so soon:
A finite straight line has two sides and can be considered a regular n-gon where n = 2. (This line is also a rectangle with length, but 0 width, an ellipse with one axis = 0, an isosceles triangle with base = 0, and so on. In every case it has two sides.) Is there a correct "gon" term (besides" line segment") for this shape? A bigon? duogon? digon?
Thanks in advance for your help. William has lots of reasons to be interested in this shape which he looks forward to sharing when he gets online.