What is metadata? The wife is the search queen, so she must have a lot.
Metadata, as sort of referenced by the Kitty Cat, is "data about the data".
A simple example is uploading a photo.
If you take a photo on, say, your iPhone, and upload it, that photo has associated with it a bunch if intrinsic metadata.
Notably format (JPEG, GIF, PNG, etc.), size (640x480), etc. Those are the simple ones.
Then it gets better.
You phone (likely) tagged it also with: the location, where it was taken, the direction you're facing, the time of day it was taken, the phones orientation (upside down pictures anyone?), the zoom factor, aperture, exposure, etc.
Next, when you upload it, the place you uploaded it to now knows not just everything that's on the photo but where you uploaded it from, when you did that, what your ID is, what type of machine you uploaded it from, etc.
All that from a photo.
Then you take on things like Facebook, with their friends list, and facial recognition, and other image analysis. they know not only do you take photos, but you take photos of your friend Joe. And Sam. And Bob. And, hey, Bob takes photos of you. And Sam. And Joe. And they were all at that party you had on 3:32 PM at 1234 Main St, Anytown USA. If they look some more, they may identify the beer your drink, if you like to barbecue, whether that location has a pool.
That's all metadata.
For more metadata fun, consider the stores that track you when you walk in the store by seeing your phone ping their wifi. They track that throughout the store, so they see you browsing the soup aisle. And then they know. "Hey, phone with MAC Address 12345678 used credit card number 1234 4567 8901 2345 at 12:35 pm purchasing butter, Snickers, April 2019 Cosmopolitan and breath mints for $12.34.
And, oh, hey, CC# 1234...2345 is You! He's 52, owns his house, 2 cars, has a dog, a daughter in college....
Yea, meta data is a hoot.
(Shall we discuss what the license plate reader that saw you drive in the parking lot knows about you?)