Explain nothing. I mean, explain the word nothing. N-O-T-H-I-N-G!
Something very hard to see and hard to understand,
yet people say it quite simply,
as if a grain of sand.
So please explain this noun to me,
as I am quite unsure.

Darkness is sometimes explained as being the absence of light.
With that in mind I might hazard that "nothing" is the absence of "something".

A quantity or thing of no importance or value.
A non-existent thing.
Not anything.

You can think about this in many different ways. It's up to all of us to discern our own meaning of nothing.

Nothing is what we make it. If something is not important enough to hold your attention, it's nothing to you.

Two of these are as clear as mud! Geez, nothing is non-existent...so nothing is nothing in the sense of the word!