AElflaed note: This was lifted from Cathyn's website so I could edit and preserve it. It might still be out there elsewhere as well.
Courage comes from the French root coeur, which means "heart." In English, the words "heart" and "courage" are interchangable. Courage is looking adversity of any sort in the eye, and standing to face it. Courage is standing up for one's beliefs, in the face of danger, and in the face of peer pressure. Courage is doing what is right, rather than what is easiest.
Courage is not always prudent, Courage is not always smart. People have used their Courage to save lives, others have died for their Courage. Live or die, Courage is not a virtue of regret. The Courageous look back at their acts and realize that they did what had to be done, and they were possibly the only ones willing or capable of putting themselves at risk to make sure it got done.
I will cite no real-world examples of Courage, as there are too many, and I would rather not tarnish the others by mentioning just one. We all know Courage when we see it.