>he world has come to agreement

No, it hasn't. I commonly use PT myself which doesn't fit that format. It's the timezone that the west coast of America uses which makes it very convenient if you live there instead of having to remember if the day your meeting on is with or without daylight savings. The three timezones we use here are:

PT: The time of the day that all of our clocks are going to be set to.

PST: The time when daylight savings is not active.

PDT: The time when daylight savings is active.