How come we define nothing, if nothing isn't supposed to be anything at all?

Other than the word ’‘nothing’’ being conventionality used to denote the absence of something, is there anything else to it? I mean nothing can’t, as we technically define it, be ’‘nothing’’, because as soon as we give it a description, it becomes something.
I mean beyond that an empty glass does have air in it, that there isn’t anything in it makes that ’‘nothing’’ be that ’‘not anything’’. And that is no longer nothing, (nor was it ever) whether it denotes just that, or not. Er, what the hell am I talking about.
We have words like ’‘void’’ or absence thereof, but in my mind those all relate to how nothing can’t be what we say it is. What is true nothingness? Like, maybe what it’s like before we’re born and when we die? It could technically be nothing, but only because someone can’t come from before they’re born, or come back from the dead to tell us. And if they could, as soon as they give the description of what they experienced, again, it’s no longer nothingness.
Before either God came into existence or before the Big Bang happened, we say there wasn’t anything around. Going by what I think is logic, there forcibly had to have been something there. There couldn’t just not have been anything. That’s impossible! (I think…) Even if say, it was just some big neverending whiteness, that whiteness isn’t ’‘nothing’’, unless nothing actually has a source and a face. And if it does, it still doesn’t match what we understand it as, besides the convenience of saying something isn’t there.
Sorry if this is confusing. I just never quite understood how we can know what true nothingness if it’s something we recognize and define. Something that goes beyond everyday word usage, emotional states, cultural recognitions of things that don’t exist but that everyone talks about anyways, or metaphors and what have you. Maybe there just isn’t anything besides the human subscription to convenience? Lol. I mean I can only go at this with what feeble human logic and understanding of things that I posses. Any thoughts?