center} Initialisms and Acronyms
RULE # 1a Use periods for initials that stand for given names (names given at birth).
RULE # 1b A space follows each period in initials for given names.
E. B. White, John Q. Adams, Harry S. Truman, J. K. Rowling, J. R. Ewing
RULE # 2 Do NOT use periods when a person's entire name has been replaced by initials (letters). No spaces are needed between letters.
JFK, FDR, MLK, LBJ
RULE # 3 Do NOT use periods with abbreviations that appear as all capital letters, even if lowercase letters appear in the middle of the abbreviation.
FBI, CIA, NCIS, PhD, EdM (master's degree in education), LLD (doctor of laws)
DVD, VCR, PC, DVR, PhG (graduate in pharmacy)
HIV, TV CEO, ME (Medical Examiner), URL (Uniform Resource Locator)
Washington D.C. Has Its Own Rules.
RULE # 4a D.C. remains abbreviated when it follows Washington.
RULE # 4b A comma follows Washington in Washington, D.C.
RULE # 4c A period follows the D and the C in D.C.
RULE # 4d There is no space between the period and the C in D.C.
RULE # 4e District of Columbia is spelled out when it stands alone in a sentence. It is preceded by the word the.
The seniors enjoyed their field trip to Washington, D.C.
The District of Columbia is densely populated.
RULE # 5
The following initialisms are ALWAYS abbreviated when writing prose:
RULE # 6 Familiar initialisms that are in all capital letters should be written in their abbreviated forms, even when writing sentences (prose).
FBI, ABC, YMCA, TV, VCR, DVD, HIV, DNA
RULE # 7a When an abbreviation that ends with a period comes at the end of a sentence that requires a period, do not add a second period. One period punctuates both the abbreviation and the sentence. Never put two periods together.
Rita overslept; she intended to leave at 9:00 a.m. (No second period is needed because one period punctuates the abbreviation and the sentence.)
RULE # 7b When an abbreviation that ends with a period comes at the end of a sentence that requires a question mark or exclamation mark, punctuate the abbreviation with the period, then add the question mark or exclamation mark to punctuate the sentence.
What a tragedy it would have been, had the hi-jacked plane reached Washington, D.C.!
(The period punctuates the abbreviation; the exclamation mark punctuates the sentence.
Do you have anything scheduled for 2:30 p.m.?
(The period punctuates the abbreviation; the question mark punctuates the sentence.)
When is the class field trip to Washington, D.C.?
There are never two periods at the end of a sentence.
When a question mark or exclamation mark is needed in a sentence that ends with a.m., p.m., D.C., Jr., or Sr., you should use the period that punctuates the abbreviation AND the question mark or exclamation mark that punctuates the sentence.
Using a or an Before Abbreviations
RULE # 8a If the first letter of the abbreviation makes a consonant sound when you pronounce it, use a.
RULE # 8b If the first letter of the abbreviation makes a vowel sound when you pronounce it, use an.
The choice of a or an is determined by the way the abbreviation sounds when read aloud.
It doesn't matter what it starts with.
The important thing is the vowel or consonant sound.
Let's take a closer look. The abbreviation FBI starts with an F. So, do we precede it with a? No.
Listen to the sound the F makes. Eff-Bee-I is what we actually hear when we say it.
Eff makes the vowel sound of Eh at the beginning of the initialism FBI. Therefore, we use an.
Mary Shannon is a FBI agent working in the Witness Protection Unit.
Mary Shannon is an FBI agent working in the Witness Protection Unit.
Let's look at another example. UFO begins with a vowel. Do we precede it with an? No.
Listen to the way we pronounce UFO. Yoo-Eff-O is what we hear when we pronounce it.
We hear the consonant sound that Y makes. Therefore, we use a.
Miss Bee wrote a poem about an encounter with an UFO.
Miss Bee wrote a poem about an encounter with a UFO.
Think about these:
an NCO (En-See-O)
an MP (Em-Pee)
an NBA coach (En-Bee-A)
an HIV test (Listen for the A sound—Aych)
an AA meeting
a AA battery (pronounced "double A")
a URL (Yoo-Arr-Ell)
a PTO meeting
Pay attention to these two examples:
an AA meeting
a AA battery (pronounced double A)
RULE # 10 Chicago generally prefers the all-capital form of acronyms, unless the term is listed otherwise in Merriam-Webster's Dictionary. (That is Chicago's preferred dictionary.)
The following is a list of some of the more common acronyms. These are Chicago's preferred spelling of these acronyms.
When you don't know whether to use all capitals or not, look it up. It's only a click away.
NATO, NASA, AIDS, ERISA
laser, radar, sonar, scuba
RULE #11a Familiar acronyms should be left in their abbreviated forms when writing sentences.
NATO, NASA, AIDS, laser, radar, sonar, scuba
RULE # 11b The first time that less familiar acronyms and initialisms appear in writing, they are written out in their abbreviated form, but the abbreviation is also spelled out and placed in parentheses to ensure that the reader knows what the abbreviation stands for. After that first appearance, only the abbreviated form is used.
ERISA, WLLN, CGI, HVAC, MLA
When preparing your term papers, you must use MLA (Modern Language Authority) formatting. All deviations from MLA formatting will cause your grade to be reduced.
Initialisms and Acronyms
DEFINITION # 1 An abbreviation is any abbreviated form of a word, phrase, or group of words.
DEFINITION # 2 An initialism uses the first letters of several words.
DEFINITION # 3 An acronym uses the first letters of several words and forms a word of its own.
The initials are pronounced as a single word.