What do you call the line segment that connects each straight line segment of a polygon?

The term that describes the line segment connecting each straight line segment of a polygon is "side." In geometric terms, a polygon is defined as a closed figure made up of straight line segments that connect at vertices. Each of these straight line segments is referred to as a side. For example, in a triangle, there are three sides; in a square, there are four sides.

Understanding the terminology is essential for grasping more complex concepts in geometry, such as calculating the perimeter of a polygon or determining the relationships between its sides and angles. The other terms pertain to different aspects of polygon geometry: a vertex refers to the point where two sides meet, an edge can refer to any side of a polygon but is more commonly used in three-dimensional shapes, and a diagonal is a line segment that connects non-adjacent vertices within the polygon. Thus, recognizing that the line segment between each straight segment in a polygon is specifically called a side helps in foundational geometry learning.