Wiktionary
n. The three-dimensional reproduction of architecture, geometric patterns, and everyday objects, on various scales, using cut-out and folded paper, usually thin cardboard.
Wikipedia
Origamic architecture involves the three-dimensional reproduction of architecture, geometric patterns, everyday objects, or other images, on various scales, using cut-out and folded paper, usually thin paperboard. Visually, these creations are comparable to intricate 'pop-ups', indeed, some works are deliberately engineered to possess 'pop-up'-like properties. However, origamic architecture tends to be cut out of a single sheet of paper, whereas most pop-ups involve two or more. To create the three-dimensional image out of the two-dimensional surface requires skill akin to that of an architect.