A device made of wire, wood or zinc (or any combination thereof) having openings of .163 to .164 inch, which permits workers to pass but excludes queens and drones; used to confine the queen to a specific part of the hive, usually the brood nest.
In beekeeping the queen excluder is a selective barrier inside the beehive that allows worker bees but not the larger queens and drones to traverse the barrier. The queen excluder is either a sheet of perforated metal or plastic or a wire grid in a frame. The openings should be limited to 0.163 inch (4.14 mm).