How would you define a hero?

How would you define a hero?
For my essay on ‘Heroes and the Heroic’ I am trying to discover how other people would define that phrase. So could you please answer these three questions for me? Thanks!
1. What is a hero?
2. What in your opinion is a heroic action?
3. Who do you think is a hero in the modern day? It can be anyone; a celebrity, a fictional character, a friend, a family member, etc.
Thanks once again!

A hero is someone who can go through immense sacrifice for the sake of others. The larger that sacrifice, the bigger the hero. It isn’t asked from them, they simply do it because they want to, for whatever reason.

There are the obvious actions, like charging into a burning building, or pushing someone out of the way of an incoming vehicle, but then there are the ones we don’t hear about. A teacher who remains where they are in life, even though they know they could make more money, because they want to teach and give something to the next generation. The nameless benefactor who gives an absurd amount of money to a disaster relief fund.

However, the world is in desperate need of more heroes. I can’t think of any right this second, and that’s disappointing. We need to applaud their actions, we need to report on them every day, show that there are self-sacrificing people who give hope that there is a decent human being somewhere in the world. We need more heroes.