Noun

1. Small hinged panel, usually cut into a door, with an opening just big enough for a cat to enter.
   • 1984, Arthur Hailey, Strong Medicine, Doubleday, ISBN 0385180144, p. 340,

     Then, one Saturday when Martin was working but Yvonne wasn't, she brought a saw and other tools with which she constructed a hinged "cat flap" in a rear down-stairs door. It meant that the cats were free to come and go at any time, the effect being healthier for the pets and for the household.

   • 1988, Fay Weldon, The Heart of the Country, Viking, ISBN 0670818755, p. 142,

     Jane had sealed up the cat flap, closed the ever-open window of the laundry, but there the cat somehow managed to be, staring up with a look of dependence.

   • 2006, Louise Rennison, Startled by His Furry Shorts, HarperCollins, ISBN 0060853840, p. 104,

     I let the cats out because they couldn't be arsed going through the cat flap. They were just sitting in front of the cat flap and yowling.