Metta World Peace -- Is Labor Day for Slaves?

Metta World Peace can totally school you on the difference between Memorial Day and Veterans Day -- but Labor Day is still an issue ... as evidenced by his run-in with the world's worst tutor, aka our camera guy.

You'll recall, Metta made a Memorial Day flub when he posted, "Happy Labor Day" on Twitter -- but the Lakers star has learned a lot since then, telling us... "Memorial's for guys that served and passed away." Great.

But then MWP says, "I still don't know what Labor Day is" -- and you gotta watch Metta and our camera guy work the problem. Their semi-educated guesses include honoring slaves, Mount Rushmore workers, and "people that passed away, maybe laying brick?"

For the record, according to the U.S. Dept. of Labor ... "Labor Day is a creation of the labor movement and is dedicated to the social and economic achievements of American workers."