Cadence is Celestia's adoptive niece what does that mean?

[cider float 2,539]

Okay so according to the wiki Cadence is Celestia's adoptive niece so my guess Celestia has a sister that adopted Cadence? Who is this sister anyway?

[yayayayayala 1,668]

In my opinion, it actually means Celestia became Cadance's "aunt." Celestia probably didn't want to adopt Cadance as her daughter, because that would technically make her the heir to all of Equestria, which would be too much for Cadance XD (especially because she rules over the Crystal Empire exclusively now) so she chose niece instead. :3

[cider float 2,539]

I was trying to connect the dots to how Celestia would be to Twilight. Cadence is now Twilight's sister in law so Celestia and Luna are now Twilight's adoptive aunts in law. Mind blowing.