Line segments that form a polygon are called its sides.
Chat with our AI personalities
A line segment in a polygon connecting any two nonconsecutive vertices is called a diagonal.
If I understand what you mean, then another way to say is "No two of its vertices can form a line segment that falls outside of the polygon". In that case, it is called a convex polygon.
It's called a side or edge.
The points where the line segments that form a polygon meet (i.e., the corners) are called the vertices of the polygon. The singular form is vertex.
A segment.