# The formal name (or correct term) of a plane bounded by 4 segments

We can define a plane with:

$$ax + by + cz + d = 0$$

However we assume all the variables above are $\in \mathbb{R}$.

Is there a formal name for a plane that is bounded by four line segments, or bounded to some finite area?

This may be analogous to when we differentiate a line from a segment, however I'm not sure if a term exists or if we would just call them a "square" or "rectangle" that happen to be in a 3D coordinate system.

Or is my definition wrong and a plane also includes a bounded area?

• You are talking about a trimmed surface Aug 9 '18 at 19:57
• Polygon, or $4$-gon.