The period is one of the most basic punctuation marks. Its primary role is to indicate the end of a sentence. However, confusion sometimes arises when combining the period with other punctuation marks or elements such as parentheses, abbreviations, and quotation marks.
Multiple Punctuation
If a sentence ends with a question mark or an exclamation point, the period is omitted.
Correct: I have never read What’s Eating Gilbert Grape?
Incorrect: I have never read What’s Eating Gilbert Grape?.Correct: He works at Samsung!
Incorrect: He works at Samsung!.
Periods with Abbreviations
When a sentence ends with an abbreviation, the period used for the abbreviation also functions as the period for the sentence. This rule also applies if the abbreviation is inside a quotation.
Correct: My uncle works for Warner Bros.
Incorrect: My uncle works for Warner Bros..Correct: She mentioned, “The event starts at 9:00 a.m.”
Incorrect: She mentioned, “The event starts at 9:00 a.m.”.
Direct vs. Indirect Questions
While a direct question ends with a question mark, an indirect question ends with a period.
Direct Question: What time will they arrive?
Indirect Question: I wonder what time they will arrive.
Direct Question: Can anyone attend the meeting?
Indirect Question: He asked whether anyone could attend the meeting.
Periods and Parentheses
When a parenthetical phrase occurs at the end of a sentence, the period should be placed outside the closing parenthesis if the parenthetical is part of a larger sentence.
Correct: The concert is in September (right after the summer break).
Incorrect: The concert is in September (right after the summer break.).
If the entire parenthetical is a separate sentence, the period goes inside the closing parenthesis.
Correct: She made a delicious cake. (It was her grandmother’s recipe.)
Incorrect: She made a delicious cake. (It was her grandmother’s recipe).
Periods and Quotation Marks
When a sentence ends with quoted material, the period is placed inside the closing quotation marks, even if the period is not part of the original quote.
Correct: She said the word “kindness.”
Incorrect: She said the word “kindness”.
However, if the quoted material ends with a question mark or exclamation point, the period is omitted.
Correct: He asked, “Do you know where the library is?”
Incorrect: He asked, “Do you know where the library is?”.
Periods with Abbreviations
Periods are also used in most lowercase or mixed-case abbreviations, but many uppercase abbreviations omit the period. However, some traditional uppercase abbreviations (especially academic degrees) retain periods.
With Periods: a.m., etc., U.S., J.D., vol., Inc.
Without Periods: FBI, NASA, TX, PhD, ATM, kg
Remember to maintain consistency when using periods with abbreviations in your writing.
One or Two Spaces?
In the age of typewriters, it was common to use two spaces after a period at the end of a sentence. However, modern writing, especially on computers, uses only one space after a period.