short-legged flightless birds of cold southern especially Antarctic regions having webbed feet and wings modified as flippers
"The penguin, a short-legged flightless bird found in the cold Antarctic region, swims gracefully using its wing-modified flippers and webbed feet."
Any of several flightless sea birds, of order Sphenisciformes, found in the Southern Hemisphere, marked by their usual upright stance, walking on short legs, and (generally) their stark black and white plumage.
"The waddling penguin stood tall on its short legs to watch the waves crash against the icy shore of Antarctica."
In plain English: A penguin is a flightless bird that lives mostly near cold water and swims well but cannot fly.
"The penguin waddled across the ice to catch its food."
Usage: Penguins are exclusively marine birds that cannot fly and live only in the Southern Hemisphere. Do not confuse them with penguins or other flightless land birds like ostriches.