It's a Fowl, actually!

Welcome to today's installment of "I Don't Think that Word Means What You Think it Means."

If you are near the man called Penguin, you will often hear strange stories and riddles. I remember one in particular from when I was a boy.
I was staring blankly off into space, when a man, much like you or I, found that a skeleton had been found. In his excitement, he made a fatal mistake. He made known his discovery.
"Wow! That's cool. They found a new dinosaur skeleton near by," he said.
This news drew interest from those around him, but most notably from Penguin.
"Do you know what the closest living relative to a T-Rex is?" Asked Penguin.
"No," said the man. "But I bet it is a bird of some kind."
"You are wrong!" Exclaimed Penguin. With a look of satisfaction in his eyes, he continued. "It is a chicken."
Many of us, having some remote idea as to what a chicken was, found a flaw in this statement. I forget who first pointed out this flaw, but I recall it being some kind of ape.
"A chicken is a bird." the ape stated with a great deal of confidence.
"No," retorted Penguin. "It is a fowl actually."
Stunned silence permeated the room. Once again Penguin had demonstrated his superior knowledge.
But wait! What is that you say? Fowl is another word for bird? How dare you doubt the word of Penguin? How could anyone doubt Penguin? This is how:
"But, fowl is another word for bird," responded the man. That very same man who dared speak of the bones that began this fearful conversation.
Penguin, not willing to let those less informed than he fall prey to false words, knew exactly what to say to this.
"No it's not. Because a penguin is a fowl and it's not a bird."
Sensing a pattern to the exchange, the ape felt it was safe to venture a guess. A guess founded on nothing but it's own intuition.
"Yes it is."
Once again silence. How could this be? Had someone actually found a flaw in the great Penguins expansive knowledge? At the time, it seemed that way.
"Well, if you want to get technical about it." Once again Penguin had found the one thing he could have said to defend his position.
Chastened, the ape sat in it's chair, clearly defeated.