From The Collaborative International Dictionary of English v.0.48 [gcide]:
Bay window \Bay" win"dow\
1. (Arch.) A window forming a bay or recess in a room, and
projecting outward from the wall, either in a rectangular,
polygonal, or semicircular form; -- often corruptly called
a bow window.
Syn: bay window, bow window, bow-window.
[1913 Webster + WordNet 1.5]
2. a protruding abdomen. [informal]
Syn: belly, paunch, pot, potbelly, corporation, tummy.
[WordNet 1.5]
From WordNet (r) 3.0 (2006) [wn]:
bay window
n 1: slang for a paunch [syn: pot, potbelly, bay window,
corporation, tummy]
2: a window that sticks out from the outside wall of a house
[syn: bay window, bow window]