What are The Origins of a.m. and p.m.? These abbreviations represent the Latin phrase ante meridiem and post meridiem which mean before midday and after midday. They have been in use in English since the 17th century. What is the Correct Form when writing the time : A.M. or a.m. or am? Other Related Links: • What are the Canons of Etymology? • Was the first computer Bug a real insect? • I'm sure I know The Origin of The Word... • What is the origin of the phrase Sleep Tight? • What are The Origins of a.m. and p.m.? • Batsman who makes no runs at cricket is said to be Out for a Duck. Why? • What is the origin of Love meaning nil in tennis scoring? • What is the origin of the phrase : The Bee's Knees? • What is the origin of the term Flea Market? • What is the origin of the term Dressed to the Nines? • What is the origin of the word OK? • What is the origin of the word Jaywalking? • What is the origin of the word Grockle? • What is the origin of the word Codswallop? • What is the origin of the term Brass Monkey? • What is the origin of the word Snob? • What is the origin of the word Quiz? • What is the origin of the word Posh? • What is the origin of the word Penguin? • What is the origin of the word News? • What is the origin of the word Lukewarm? • What is the origin of the word Love? • What is the origin of the word Loo? • What is the origin of the word Nous?