Full Stops (Periods) in Abbreviations

Full Periods (Full Stops) in Abbreviations

Abbreviations can be written with or without periods (full stops). Often, you have a choice. In other words, you can write:

• C.N.N. or CNN
(These are uppercase abbreviations.)
• e.g. or eg
(These are lowercase abbreviations.)

Whatever format you use, be consistent. The most common format is to omit periods in uppercase abbreviations (for example, CNN, ITN) but to use them in lowercase abbreviations (for example, e.g., p.m.).

If the abbreviation is a proper noun (e.g., a company name), copy the official version.

We're Not Talking about Contractions

This guidance does not apply to titles such as Mrs., Mr., Ms., Dr., Prof., Capt., Gen., Sen., Rev., Hon., and St. Read more about using periods in titles.

More about Periods (Full Stops) in Abbreviations

It is considered untidy to mix abbreviations with periods and ones without periods in the same article. These two examples have been marked as correct because the writer has been consistent.

• The band toured around the UK and the USA last year.
• The band toured around the U.K. and the U.S.A. last year.

These next two examples are marked wrong because the writer has been inconsistent.

• It was only shown on CNN and not B.B.C.
(This is an inconsistent use of full stops (periods). It is considered untidy.)
• The M.D. asked her PA to clean the company car.
(Untidy)

The Tendency: Use Periods Only in Lowercase Abbreviations

Abbreviations made up of capital letters tend not to have periods, but abbreviations made up of lowercase letters tend to have them. For example:

• BBC
(British Broadcasting Corporation)
• LRS
(Linear Recursive Sequence)
• CBS
(Columbia Broadcasting System)
• a.m.
(ante meridiem - before midday)
• p.m.
(post meridiem - after midday)
• i.e.
(id est - that is)
• e.g.
(exempli gratia - for the sake of an example)
• p.p.
(per procurationem - by the agency of)

Note: This is a tendency not a rule.

If the abbreviation is a proper noun (e.g., a company name), copy the official version. For example:

• Our team was hosted by the Italian club A.S. Livorno Calcio.
("A.S. Livorno Calcio" (with periods) is the name shown on the logo and in all correspondence.)
• The shop will be taken over by the clothing company s.Oliver in June.
("s.Oliver" is the official version.)
• We will meet at P.F. Chang's in Tokyo.
("P.F. Chang" is the official version.)

Note: Do not worry about this point. There are very few companies who use periods in their names. I mean almost none.

Do Not Use Two Periods If Your Sentence Ends with an Abbreviation

If your sentence ends with an abbreviation (including a contraction like "etc.") that ends with a period, do not use a second period to show the end of the sentence. However, other end marks (such as question marks, exclamation marks) should be used. For example:

• I need milk, bread, cheese, etc.
• She moved from C.N.N. after an irresistible offer from the B.B.C.
• She moved from C.N.N. after an irresistible offer from the B.B.C..
(Logically, this is correct, but it is too unwieldy.)
• Will she move back to the B.B.C.?
(This is correct, but it looks a little scruffy. To avoid this, use BBC instead of B.B.C.)

The only exception to doubling up end marks with periods is ellipsis (...). For example:

• Standing tall and with the Lord's Prayer mumbling across our lips, we entered the chamber...."
(This ends in four dots: three for the ellipsis and one to end the sentence.)

Beware!

"In Other Words" or "For Example"?

The abbreviation "i.e." (id est) means "in other words" or "that is to say." The abbreviation "e.g." (exempli gratia) means "for example." Do not confuse the two.

• I study wild dogs (e.g., wolves and jackals).
("For example" fits here, so "e.g." is correct.)
• I study wild dogs (i.e., ones that are not domesticated).
("In other words" fits here, so "i.e." is correct.)
• I study different types of amphibians (i.e., frogs).
("In other words" does not fits here, so "i.e." is wrong. It should be "e.g.")

Read more about "i.e." and "e.g."

Etc. Etc.

The abbreviation "etc." is a contraction of et cetera. However, it is often mistakenly written as "ect." (This is because many people pronounce it "eccetra.")

• For a small monthly bonus, you can present staff with shop tokens, flowers, chocolates, theatre tickets, ect.
(This should be "etc." Remember to include the period with "etc.")

Finish the Abbreviation

If using periods in abbreviations, ensure you give the last letter a period too.

• I know the C.N.N set-up quite well.
(There should be a period after the last N.)

Here is a real-life example:

• 
(This garage sign in the UK should say "M.O.T.")