Heroism can be defined as ordinary people doing extraordinary acts of courage.

In recent weeks we’ve seen several Americans sacrifice for others. One is a 15-year-old Florida student who shielded classmates from a school gunman. The other, a 29-year old Tennessee man, single-handedly tackled and disarmed a mass shooter at a restaurant.

Although it occurred 16 years ago in Afghanistan, we just learned about the actions of our third brave American — an airman who sacrificed his life for his comrades — thus qualifying him for a Medal of Honor, the nation’s highest award for valor.

Our first case involving the Florida teen occurred when a gunman opened fire in February at Marjory Stoneman Douglas High School in Parkland, Florida. Fourteen students and three staff members were killed in the attack and 17 were wounded.

As the gunman sprayed bullets, Peter Wang, a cadet in the school’s Junior Reserved Officers’ Training Corps program, was last seen holding doors open so others could quickly exit a classroom. One teacher said that Wang alone saved anywhere between 10 and 20 lives.

Wang and two other Junior ROTC cadets killed in the massacre — Alaina Petty and Martin Duque — were posthumously honored by the U.S. Army with the ROTC Medal for Heroism.

It was Wang’s dream to attend the U.S. Military Academy and a week after his death he was given a rare posthumous admission to West Point.

The academy tweeted this about the extraordinary young cadet: “One of USMA’s priorities is to develop leaders of character who are committed to the values of Duty, Honor & Country. Peter Wang’s actions on Feb. 14 are an example of those principles & the academy honors his dream of being a West Point cadet with a 2025 letter of acceptance.”

An online petition urged that Wang receive full military honors at his funeral, and former veterans and members of the Patriot Guard Riders escorted his hearse. During the ceremony, Cadet Maj. Marshall Ryan called him “a hurricane of sunshine.”

Our most recent act of heroism occurred during the Sunday morning shooting two weeks ago at a Waffle House in Nashville. Although he doesn’t consider himself a hero, James Shaw Jr. was hailed for putting his life on the line after four patrons had been killed.

Shaw entered the restaurant about two minutes ahead of the suspect and was seated at a counter when the gunman opened fire. Shaw rushed the shooter, grabbed the hot barrel of the semi-automatic rifle and threw it over a counter.

After wrestling with Shaw, the suspect ran off but was arrested a day later after massive manhunt.

Shaw’s father questioned the choice his son made to charge a man with a loaded gun, but he did take pride that his son’s decision helped save other lives.

After the incident, Shaw Jr. was treated for a wound where a bullet grazed his elbow and for burns to the hands suffered when he grabbed the hot barrel of the weapon. He then went to Sunday church services with his family.

Shaw later put together a GoFundMe to help raise money for the families of the victims.

Our third hero is Tech. Sgt. John Chapman, a combat controller who was killed during a fierce battle in Afghanistan in 2002, and is buried in Windber, Pennsylvania, (Somerset County).

Chapman originally received an Air Force Cross, the second-highest valor award an airman can receive, for a battle against al-Qaida fighters, thus becoming the first combat controller in history to earn that award.

But new video from a Predator drone showed that Chapman was not dead, but unconscious, when the battle intensified. Enhanced footage suggests that after regaining consciousness, he resumed fighting al-Qaida members approaching on three sides. One enemy fighter was killed while charging Chapman, and another was killed in hand-to-hand combat.

The Navy SEAL team leader credits Chapman with saving the lives of the entire rescue team.

The new revelations on the battle prompted former Air Force Secretary Deborah Lee James and Rep. Duncan Hunter of California to recommend that Chapman’s Air Force Cross be upgraded to the Medal of Honor. This would make him the first airman to receive a Medal of Honor for actions since the Vietnam War.

Three American heroes. One a soldier, another a teenager aspiring to attend one of the nation’s elite military academies, and the third a civilian who found the inner strength to charge and disarm an active shooter at a restaurant.

We’re fortunate to have Americans like this living among us.

By Jim Zbick | tneditor@tnonline.com