Windowpane \Win"dow*pane`\, n.

1. (Arch.) See Pane, n., (3) b . [In this sense, written also window pane.]

2. (Zo["o]l.) A thin, spotted American turbot (Pleuronectes maculatus) remarkable for its translucency. It is not valued as a food fish. Called also spotted turbot, daylight, spotted sand flounder, and water flounder.

Source: Webster's Revised Unabridged Dictionary (1913)