Common parlance is full of various idioms and words that are used without a second thought for what they really mean, or where they originated. Most people will be familiar with times of the day being expressed as either am or pm, but one X user was brave enough in a recent post to admit they didn't know what the letters am and pm stood for, and asked the internet for answers.In their recent post,@ IAMTOINEJ said:" I might be called stupid after this, but WTF does'AM' and'PM' stand for?... " It