I don't know what Labour Day is

If it’s Labor Day, why are we all staying home?

In Australia,Labor Day isn't observed as a national holiday;the date varies from state to state.In my state,it is the first Monday in October.

It's when the laborers don't labor. They do, or many of them do, but that's the idea - celebrate those who labor by giving them a day off.

Nothing to do with being in labour.

It's Labor (sic) Day, because it's a US holiday.

Context clues tell me it's when all the women coordinate and give birth together.