OK, meta data, meta tags, meta descriptions, meta description tags . . . hands up who knows what they are?
This definition from tech terms is helpful
Meta data is data about data, it provides information about an item’s content.
And the specific areas of meta data on a web page associated with specific information are called meta tags, so you will get meta keyword tags and meta description tags / meta descriptions.
Whether you know all this or not, the one thing I can guarantee . . .
You all will have seen these meta descriptions and read them, even if you don’t know what and where they appear.