English punctuation and capitalization rules for abbreviations vary widely because those rules frequently change. Moreover, American and British English differ in the use of periods with names and titles of people. Therefore, you should think of the “rules” for abbreviations as guidelines, not absolutes. Always make sure that the abbreviations you use are consistent with the style guide for your company or field of work.
In the previous lesson, we covered general guidelines for abbreviations and abbreviations for the titles of people. This week, we’ll turn our attention to abbreviations for dates and times and familiar abbreviations that you can use safely in most types of writing.
Dates and Times
BC (“before Christ”) refers to dates before the beginning of Western calendar time. Place the abbreviation after the year:
100 BC (B.C.)
AD (anno Domini, “in the year of our lord”) refers to dates after the beginning of Western calendar time. Place the abbreviation before the year:
AD (A.D.) 2017
BCE (“before the common/current era”) and CE (“common/current era”) are secular alternatives to the religiously-inspired BC and AD, respectively. BCE and CE have grown in popularity and acceptance in recent years, particularly in the fields of education and academia. Unlike AD, CE follows the number:
100 BCE (B.C.E.)
2017 CE (C.E.)
Use the one of the following abbreviations for ante meridiem (“before midday”) when writing a time between midnight and noon:
Use the one of the following abbreviations for post meridiem (“after midday”) when writing a time between noon and midnight:
Note: While all three variations of a.m. and p.m. are generally accepted, you should consistently use the same style for each.
You can use some types of abbreviations in formal writing as long as they are familiar to your audience. If your audience is unfamiliar with an abbreviation (or you think they might be), write out the complete name the first time you use it and show the abbreviation in parentheses. For example, The English Island (TEI) offers English courses in Atlanta.
Below are some categories of abbreviations familiar to most native English speakers in the United States and Canada and several examples of each:
|MIT, UCLA, UGA|
|IBM, LG, UPS|
|CIA, FBI, DMV, IRS|
|Products and Services
|ATM, DVD, PC, TV|
|ACT, SAT, GRE, USMLE|
(pronounced as words)
|NATO, NAFTA, RAM, TOEFL|