(Zool.) Any bird of the order Impennes, or Ptilopteri. They are covered with short, thick feathers, almost scalelike on the wings, which are without true quills. They are unable to fly, but use their wings to aid in diving, in which they are very expert. See King penguin, under Jackass. Note: Penguins are found in the south temperate and antarctic regions. The king penguins (Aptenodytes Patachonica, and Aptenodytes longirostris) are the largest; the jackass penguins (Spheniscus) and the rock hoppers (Catarractes) congregate in large numbers at their breeding grounds.