Grammar Punctuation for Abbreviations |
The Blue Book of Grammar and Punctuation

Punctuation for Abbreviations

Those who write in American English may sometimes wonder when to abbreviate a word as well as how to abbreviate it. This review will help address those questions.

An abbreviation is a shortened or contracted form of a word or a phrase (e.g., Mister to Mr.). If you’re ever in doubt about when and how to abbreviate a word, you can start by consulting a current dictionary or stylebook, as prevailing usage can change.

In the meantime, the following guidelines can be useful in providing direction.

Punctuation for Abbreviations: Names and Titles

Abbreviate names with a single letter followed by a period. If two successive letters are abbreviated, do not include spaces between the periods.

Franklin D. Roosevelt, Susan B. Anthony, J.P. Morgan, k.d. lang

If a person’s full name is abbreviated, use only first letters without periods: JFK (John F. Kennedy), LBJ (Lyndon B. Johnson), MJ (Michael Jordan).

Abbreviate and capitalize junior or senior if it follows an individual’s name. Many stylebooks now also allow for a comma before junior or senior to be omitted.

Ken Griffey Sr., Ken Griffey Jr., John F. Kennedy Jr., Robert Downey Sr.

If someone’s personal or professional title appears before the full name, it is abbreviated. Some common abbreviated titles are:

Reverend: Rev. Governor: Gov. Mister: Mr. Senator: Sen.
Doctor: Dr. Professor: Prof. Mistress: Mrs. Representative: Rep.

Rev. Peter Jones, Prof. Carrie Newsom, Mrs. Janette McCauley, Sen. Ken Hanson

Some stylebooks may advise to not abbreviate a professional title if it is followed only by the last name.

Reverend Jones, Professor Newsom, Senator Hanson

If a professional title follows a name, its abbreviation might not always be punctuated. A comma will also usually precede the title.

Christine Mundt, Ph.D. (Doctor of Philosophy) Mary Richards, MD (Medical Doctor)
Thomas Legend, RN (Registered Nurse) Chester Gamble, J.D. (Juris Doctor)

Punctuation for Abbreviations: Addresses, Dates, and Times

The Associated Press Stylebook advises to use abbreviated, punctuated compass points and Ave., Blvd., or St. only with a numbered address: 1060 W. Addison St., 1600 Pennsylvania Ave. but Addison Street, Pennsylvania Avenue.

Formal writing usually does not abbreviate days and months. Less-formal writing may accommodate punctuated abbreviations for specific dates. In each case, the abbreviation would be punctuated by a period.

Abbreviations for days are Mon., Tues., Wed., Thurs., Fri., Sat., and Sun. Abbreviations for months are Jan., Feb., Aug., Sept., Oct., Nov., and Dec. (March, April, May, June, and July are not abbreviated.)

Sun., Feb. 12; Thurs., Oct. 31; Wed., Dec. 9; Fri., Sept. 23, 1988

Whether to abbreviate such date formats is a matter of preference and style.

Punctuation of time is yet another style item that can vary by source. Many stylebooks will punctuate a.m. (or A.M.) and p.m. (or P.M.): 7:15 a.m., 8:05 P.M.

Zone abbreviations are typically not punctuated (EST, CDT, PST). Time eras are usually abbreviated and punctuated (B.C., A.D.).

Punctuation for Abbreviations: Acronyms and Initialisms

Although sometimes thought to be synonymous, acronyms, initialisms, and abbreviations are different categories of letters.

Acronyms are abbreviations pronounced as words (e.g., AIDS, OPEC). Initialisms are formed from the first letter or letters of a series of words, and each letter is pronounced (e.g., ABC, FBI).

Many stylebooks agree that acronyms and initialisms are not punctuated. Some examples are NATO, NAFTA, YMCA, and NAACP.

Punctuation for some initialisms can vary among style sources. For example, The Chicago Manual of Style will instruct the use of R.S.V.P., but AP will advise using RSVP.

Punctuation for Abbreviations: Other Common Uses

Other terms that are commonly abbreviated and punctuated with periods are academic degrees, units of measure, and Latin terms.

Bachelor of Arts: B.A. inch: in. id est: i.e. post scriptum: P.S.
Bachelor of Science: B.S. pound: lb. exempli gratia: e.g. et alia: et al.

Related Topics

Abbreviations vs. Acronyms vs. Initialisms
Abbreviation, Acronym
Unusual Plurals of Abbreviations

Pop Quiz

Applying what we’ve discussed, adjust any words that can be abbreviated and punctuated.

1. Darla lives at 546 West Mighty Mouse Boulevard.

2. The box weighed 35 pounds.

3. Bobby Jo Bryan Senior will receive the honors for lifetime achievement.

4. The brunch at the community center will be on Saturday, November 11.

5. Representative Fields is giving the speech at the ribbon-cutting event.


Pop Quiz Answers

1. Darla lives at 546 W. Mighty Mouse Blvd.

2. The box weighed 35 lbs.

3. Bobby Jo Bryan Sr. will receive the honors for lifetime achievement.

4. The brunch at the community center will be on Sat., Nov. 11.

5. Representative Fields is giving the speech at the ribbon-cutting event. No abbreviation or punctuation

If the article or the existing discussions do not address a thought or question you have on the subject, please use the "Comment" box at the bottom of this page.

20 responses to “Punctuation for Abbreviations”

  1. Karla Keeney says:

    I have questions after reading the email I received:

    You left out one that I’m unsure of: post office box — is it “P.O. Box 999” or “PO Box 999”?

    The preferred time period designations are now “common era” and “before common era” – CE and BCE – you don’t mention those, but shall I assume that they are abbreviated the same was as the archaic BC and AD?

    • says:

      Coincidentally, The Associated Press Stylebook advises to use periods (P.O. Box), but the U.S. Postal Service itself does not include them. In daily formal writing, you would be in step with many stylebooks by including the punctuation. In addressing a letter, you are fine either keeping or omitting the punctuation.

      For period (era) designations, both The Chicago Manual of Style and AP still use and refer to B.C. and A.D. If you choose to use C.E. and B.C.E. in formal writing, you would use the same punctuation.

  2. Don Yorath says:

    In my experience common (though not universal) usage in Australia differs somewhat in respect of several of your examples.
    1. All months are abbreviated to three letters: Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec.
    2. Days are Mon, Tue, Wed, Thu, Fri, Sat, Sun.
    3. Beginning in the early 1970s there was a drive to streamline typing, especially of names and addresses. Typical styles include –
    Titles: No punctuation, at least when the last letter of the abbreviation is the same as the last letter of the full title (Mr, Mrs, Ms, Dr), although increasingly the abbreviations such as Prof, The Hon, Rev (otherwise Rev’d), and Gov are seen without punctuation.
    Initials: No punctuation, but separated by spaces.
    Post nominals: No punctuation after the family name and no punctuation within or between post nominals (Mr J W Brown BA PhD).
    Virtually the same approach is taken with the abbreviation of addresses such as St, Ave, Rd, Apt, Lvl, and PO Box.
    These changes coincided with the introduction of proportional type fonts, resulting in reduction of the conventional number of spaces after the full stop (period) at the end of sentences from two to one.
    4. Written dates and their abbreviations in common use are: First of May – 1st May. Twelfth of June – 12th June, Twenty-third of July – 23rd July, Second of August – 2nd August.
    Interestingly, I think these changes were regarded as a move away from some of the quirks inherited from British styles and towards a more modern and streamlined American style. Increased standardisation in formatting also made setting up templates for WP functions such as mail merge simpler.

    • says:

      This is insightful and informative. It is always enlightening to consider how different cultures sharing the same language treat the presentation of it, particularly as it concerns how to best use space on a page. We hope our other grammar enthusiasts enjoy this contribution to the discussion as well.

  3. Krebben H. says:

    I wonder is it both alternatives to use or not to use dots on any initialisms? Is that the person’s choice? Can “don’t” be initialized as “DN” or just by “D”?

  4. Carla Norris says:

    What about when an abbreviation is the final word in a question?
    Where does the final period go?
    What the blazes is going on in Washington D.C.[?]

    Should it be “D.C.?” “D.C?” “D.C?.” or none of these?

    • says:

      It is correct to use a question mark immediately after an abbreviation ending in a period. Therefore, the following is correct:

  5. Kathy says:

    I was always taught that periods are used after lower case letters, not capitalized letters, e.g. AM vs. a.m., CA vs. Cal., Dr. vs. MD, and degrees as BA, MFA, JD, BS, Ph.D, and Ed.D.

    • says:

      As the post states, punctuation can vary among style sources. For example, the Chicago Manual of Style recommends omitting periods in abbreviations of academic degrees; however, the Associated Press Stylebook says, “…use periods in most two-letter abbreviations.” We suggest choosing a style guide and remaining consistent.

  6. Jagoda says:

    In the following sentence, do we need a period after the parentheses since there is an abbreviation ending in a period before the parentheses? I’m not sure what the rule is in this case.

    The sentence goes: You can park a passenger car on the smaller parking lot on Oxford St. (right beside the church).

  7. Dolores says:

    Which is better with a maiden and married name:
    Vera I (maiden name initial) Cristo, or Vera I. Cristo
    I being representation of her maiden name?
    Do we need the period fter the “I”?

  8. Nicholas Schäffer says:

    Which is the correct way to punctuate my initials for UK usage: NS or N.S.

  9. Spectral says:

    Thank you for this! The abbreviations that I’m still confused about are:
    N.Y.C. or NYC? L.A. or LA? It’s confusing because of the state of Louisiana (LA).

    — and —

    Artificial Intelligence being A.I. or AI (confusing without serifs … could be confused with a person’s name Al (AL).

    I vote for using these abbreviations with periods/full stops, but many times I see them written without.

    • says:

      According to AP Stylebook either “NYC” or “N.Y.C.” is acceptable as an abbreviation for New York City. AP also notes “We usually use New York on second reference, or the specific borough. Avoid the shorthand NYC in the body of the story unless there’s a particular reason to use it or it’s very informal writing.”

      “AI” is usually written without periods. In any context where the abbreviation is potentially confusing, avoid using it.

  10. Mike O'Toole says:

    What about when the abbreviation is at the end of a sentence? Is it correct to drop the period, as in “We left at 10 a.m. We arrived an hour later.”

    • says:

      Our Rule 2 of Periods says, “If the last item in the sentence is an abbreviation that ends in a period, do not follow it with another period.”

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