Time and Dates for Writers

What time is it?

Digital clocks might label noon "12:00 PM" and midnight "12:00 AM", but this is incorrect, and readers might be confused. It is better to simply write "noon" or "midnight" when that's what you mean. "AM" comes from the Latin phrase "Ante Meridiem", meaning "before noon". "PM" is the abbreviation for "Post Meridiem", meaning "after noon". In formal writing it is still preferable to capitalize them, but the lower case "am" and "pm" are gaining in popularity and use.

What's the date?

"A.D." means anno domini ("in the year of the Lord" or the year Jesus was born). It isn't an abbreviation for "after death". "B.C.", however does stand for the English phrase "before Christ". Coming into more popular use are the terminologies used by academics and archeologists, B.C.E. "before the Common Era" and C.E. "the Common Era". As with the abbreviations designating time, these can also be used in lower case.

Whichever format you choose, be consistent throughout a piece of writing, as I hope I have been about punctuation inside and outside quotation marks. (I choose to follow the rule of letting the punctuation appear with its logical content.)