Trivia: What is the “M” in A.M. and P.M.?
Meridiem
Middle
Midday
Moderate
Correct Answer: Meridiem
So why is this answer correct? : A.M. is an abbreviation for the Latin term “ante meridiem,” signifying “before noon.” P.M. denotes “post meridiem,” Latin for “after noon.” According to the Physical Measurement Laboratory, which is part of the U.S. Department of Commerce’s National Institute of Standards and Technology, “12 a.m. and 12 p.m. are ambiguous and should not be used.” They recommend opting for the terms “noon” and “midnight” instead.