While telling time, what do a.m. and p.m. denote?
The abbreviation `a.m.` stands for `ante meridian` while `p.m.` stands for `post meridian`. What do these terms mean? In Latin, the word `meridian` stands for mid-day or noon, when the sun is directly overhead. The noon hour divides a day into two halves, before-noon and after-noon. So, the term `ante meridian ` means `before noon` (in Latin, `ante` means `before`) when the sun is still rising in the sky. Similarly, `post meridian` is used to denote the hours after noon (the Latin word for `after` is `post`).