Pronunciation: (win'dō-pān"),[key] —n. 1. a plate of glass for filling a window sash within the frame.
2. a flounder, Scophthalmus aquosus, occurring along the Atlantic coast of North America, characterized by the thinness and translucency of its body.
—adj. designating or having a large, regular design of intersecting lines resembling a series of windowpanes: a windowpane plaid sweater.