Am I my body? A "person" is the true entity that I am. It is the "chunk" that humanity comes in. It's more specific than "being."
Here's my definition of "person": a conceptually, conscious physical unit, living and moving in a directly perceived world with other entities and people.
That might be more of a summary of my theory on the subject, rather than a true definition, but you get the idea. I know it's got a lot of moving parts, and we can discuss them one by one.
A person is a person if they are asleep or if they are in a coma they might wake up from. If they have severe brain damage and can never be conscious again, then they are not a person. I suspect a fetus past a point in its development might count as a person, but I don't pretend to know the answer to that question. In any case, I am not worried about outliers.
What I am concerned with is how people experience emotions, physical activity, sex, eating, etc. All of these things are affected by what you think you are, if you have let it sink in. For example, if you believe you are a soul, created by God and tethered to a physical body, you might believe sex is a sin.
I have been working on these ideas for many years, and I hope to publish an essay on the subject in the near future.