Can someone explain: What does indexing mean? or What does indexing mean? Need a simple explanation!

"Newbie question: What does indexing mean exactly?"

Hey guys, super confused here. I keep hearing about indexing but no one explains it like I’m 5.

So… what does indexing mean? Is it just some fancy term for organizing stuff? Like, how Google “indexes” websites—does that mean it’s just sorting them so it can find ’em faster?

And why’s it such a big deal? If a site isn’t “indexed,” does that mean it’s basically invisible?

Sorry if this is dumb, but I’m lost lol. Anyone got a simple breakdown?

(Also, is it the same thing in databases? Heard that term thrown around too.)

Thanks! 🙏