It's a word that actually refers to a very simple thing.
In computer systems, metadata is basically the information of the file (i.e. file size, date created, date modified, etc.)
Metadata is—for the most part—specific depending on the type of file. For music and video files, it can include information such as length, bitrate, artist, title, resolution, etc etc.
"Before sharing the document, make sure to remove any sensitive metadata such as author names, revision history, and comments to protect the privacy and confidentiality of the file"
12 step recovery jargon referring to someone new who talks about how great life is, now that they'resober. Usually meaning that the person is out of touch with reality.
The new guy seems pretty happy for a dude who has no job, no money and no family. He must be on a pink cloud.