What is "Public Health"?

Without googling, what do you think it is?

I want to know what others think it is. I know what it is, that's why I'm majoring in it.

People always ask me (irl) what I'm going to school for and I tell them public health. Their response is usually " oh, so you want to inspect restaurants"? That is a part of public health (health inspector), but that is not all public health is.