The Collaborative International Dictionary of English v.0.48:
Rectangularity \Rec*tan`gu*lar"i*ty\ (-l?r"?*t?), n. The quality or condition of being rectangular, or right-angled. [1913 Webster]WordNet (r) 3.0 (2006):
rectangularity n 1: the property of being shaped like a rectangle [syn: rectangularity, oblongness]