Definition of: penguin

(pen′gwin. peng′-) noun
1. A web–footed, flightless, aquatic bird (genus Spheniscus) of the southern hemisphere, with flipperlike wings, short legs, and plantigrade feet.
2. Originally, the great auk.
3. Aeron. An airplane with an engine of low motive power, so as to be incapable of flight: used in the early training of aviators. [Cf. F pingouin, penguyn the great auk]
EMPEROR PENGUIN
(From 3 to 3 1/2 feet tall; the largest of the flightless, swimming birds)