Shorthand for please, but nowadays since texting shorthand isn't really used, it has actually become something of a separate entity. It has made it into verbal speech, such as "lol", and is pronounced "plz" or "pluz". In this context, in in and of itself can be used to mean:
"oh please" used to call out one's bullshit.
or
"please no" a subdued beg for mercy, usually from an online roasting.
Short for "please", used in email by lazy asshats who put the minimum possible effort into being polite. Usually used in messges demanding something that's trivial for them but a PITA for you.
To all staff: Pls make sure your T.P.S. reports have the propercovers.
Parking Lot Syndrome. When a group of friends stand around in the parking lot talking and chatting after dinner, a movie, or an event. This usually occurs when deciding on what to do next and can last a few minutes. However, it's only considered PLS if it lasts a considerable amount of time.
"Let's get rid of this PLS and decide where to goalready! We've been out here in this parking lot for an hour and I wanna do something!"
Post Lunch Sleepiness: The greatest and most dangerous disorder in America today. It affects millions of American workers and or students each and every weekday of the year. The symptoms include lethargy, a strong urge to sleep no matter where you are at the moment, and an inability to focus on anything no matter how interesting it may be.
Monty: Man, I just finished lunch like an hour ago, and now I got a severe case of PLS.
Ryan: PLS?
Monty: Yeah, post lunch sleepiness
Ryan: Oh yeah, I had that real bad on Tuesday, and fell asleep under a pile of phone books in the supply room. When I woke up it was 6 at nite, and everyone was gone.
Monty: Yeah, PLS sucks.