Lt. Col. (ret.) Clay Darling has worn a lot of hats over his years. And on Monday afternoon, he demonstrated just two of those, a standard issue hairnet used in the operating room at Via Christi Hospital, and another emblazoned with the U.S. Marine Corps emblem that he used to wear.

Darling was the featured speaker at Via Christi Hospital's Veterans Day ceremony on Monday afternoon just outside the front doors of the hospital.

Darling began his remarks by noting the history of Veterans Day, but then asked what should be a simple question: What is a veteran?

"It's a word one would think would be easy question to answer. Perhaps Congress legislated a definition. They did not. Some think it's only those that serve in a foreign theatre," Darling said. "Some think it's only those who gave their lives for their country. I think a veteran is someone who, at some point in his or her life, wrote a blank check to the United States for any amount, up to and including my life."

Earlier, Via Christi Hospital CEO Randy Cason opened the ceremony with some remarks of his own. He noted the number of veterans (an estimated 25 million) that are still alive today.

"When Francis Scott Key wrote the words of the Star-Spangled Banner 200 years ago, he called America the land of the free and the home of the brave. That's as true today as it was then," Cason said.

Cason went on to quote the words enscribed on the Korean War Memorial, which reads: "Our nation honors her sons and daughters who answered the call to defend a country they never knew and a people they never met," comparing the story of the Korean veterans to that of all veterans.

"It's our privilege to thank you for all your work. We appreciated you for your service, we honor you for your sacrifice," Cason said. "The price of freedom is high. We cannot afford to forget those who pay that price."

But it was the words of Darling that ruled the day, noting a conversation he had with a woman who'd seen his Marine Corps cap and called him her hero, knowing nothing more about him than that, and encouraged others to thank a veteran if they see one.

"It's nice to be recognized. Not just for me, but all veterans, it's nice to be recognized," Darling said. "There are a lot of people out there doing things so we can be here."