Is It Joker Gas or Laughing Gas?

I've noticed that in different comics, the Joker's signature poison gas has been referred to as both "Joker gas" and "laughing gas," but which is the proper term? Are they two terms for the same gas, or does the term Joker gas refer to the more potent gas that gives people a permanent smile, while the term laughing gas refers to the relatively harmless gas that simply causes people to laugh uncontrollably?

Joker Gas is what I've known it as mostly.

that