To tabulate and print out the transactions of the day's sales on a cash register.
Metaphorically: To sum up and conclude a transaction or relationship.
"It's quitting time. Did you Z out?"
"OK, if we'regonna Z out, let's talk about the $960 I paid on your Con Ed bill 2 years ago."
when you're holding up your phone and making faces at it, as though you are taking a selfie, but you're really taking a picture of the person across from you or the wall or anything else that seems interesting but you don't want to be caught dead taking a picture of.
This action is often made more convincing by wiggling the eyebrows or opening the mouth, to pretend you're trying to get a Snapchat filter to work.