Stupid question, but. What does "meta" mean? Google won't give me a clear answer

No stupid questions! It is never stupid to educate yourself on things you don’t know!

Meta, in this case, is just a shortened way of referring to metatext. Discussing a piece of media within itself, about itself. Essentially, fandom uses it to mean talking through the narrative and character arcs while taking into account the world they are in and the themes attributed to it. Generally accepting that there might not be a real life experience to equate it to.

For example, discussing reasonings behind choices characters made and how they affect the plot because of other plot lines or backstories. Or how a plot or character choice came about at all because of the themes within the genre the media labels itself as.

You’re not necessarily looking at it as storylines and character arcs in a vacuum, you’re looking at them as parts of a whole necessarily informing each other.

That’s my understanding of it, at least.

Hope that gave you a little clarity :)