rectangle
A floor plan with 4 sides meeting at right angles and one axis longer than the other.
A rectangular building plan has a perimeter with four sides which meet at right angles, with two parallel sides longer than the other two. It can be extremely narrow or almost square, as long as it is discernably longer than a square. The corners and edges can have small irregularities such as notches, offsetting, protrusions, or chamfering.
The four principal sides enclose a plan with one axis longer than the other. Small corner or edge details are compatible with that dominant rectangular outline.
A square has principal side lengths within its stated 5 percent tolerance, while a parallelogram has opposite sides parallel without right-angle corners. Those distinctions concern the main outline rather than every small notch.