The Period
The PeriodThough a seemingly trivial punctuation mark, the period does present some knotty challenges, especially in technical writing. We all know to place a period to signal the termination of a simple sentence that makes a statement. However, here are a few more specialized rules:
- Do not use a period in combination with other punctuation marks unnecessarily, especially when a quotation is involved. In such an instance, end the sentence naturally on whatever punctuation mark is logical (e.g., a question mark).
- Avoid using periods at the ends of abbreviated units of measure, except when the period might be confused with another word. (Therefore, so that it’s not confused with the word "in," use "in." to abbreviate "inches.")
- When using a period in conjunction with parentheses, the period comes after the parentheses are closed if the parenthetical comment itself is part of the larger sentence (as in the first bulleted sentence above, and this one). The period comes inside the parentheses only when the parentheses themselves contain a complete independent sentence. (See the example in the second bulleted sentence above, as well as this sentence.)
- By convention, if an abbreviated word (such as "etc.") ends a sentence, let a single period signal the sentence’s end—two periods in a row would be incorrect.
- In acronyms commonly understood or commonly used in your field (ASTM, EPA, US, GIS), do not use periods after the capital letters.
- Do use periods after abbreviations and acronyms that are forms of address, initials within proper names, earned degrees, and when expressing measures of time (Dr. Bauer; M.S. degree; Steven S. Wilson, Jr.; 5:00 p.m.; 10 B.C.).
Self-Study
For everything you always wanted to know about the period but neglected to ask, visit these sites:
Punctuation rules from infoplease.com
English 101 Periods and Other Punctuation Project (3:49)
Transcript: English 101 Periods and Other Punctuation Project (3:49)
English 101: periods and other punctuation
Can you guess who says each punctuation rule?
Periods punctuate sentences and abbreviations.
A period marks the end of a declarative sentence or a mildly imperative one.
A period follows an indirect question.
If you guessed Mrs. Ford… free candy all around!
…Not really…
Periods follow some abbreviations.
A question mark follows a direct (but not an indirect) question.
An exclamation point shows strong feeling.
If you guessed Mr. Askins, you’ve got a green thumb! :D
Colon / dash / parentheses (red + beige slides)
A colon calls attention to what follows and also separates figures in time references, parts of scriptural references, and titles from subtitles.
A colon directs attention to an explanation or summary, a series, or a quotation.
If you guessed… Mrs. Skimmyhorn
You all earned a pie in the face!
A colon separates titles from subtitles as well as figures in time references and in citations of scripture.
The colon is also used in bibliographical entries.
A dash marks a break in thought, sets off a parenthetical element for emphasis or clarity, or follows an introductory list or series.
If you guessed Mrs. Coke
You have won a trip to Paris, France!
…Haha I wish…
A dash marks a sudden break in thought, an abrupt change in tone, or a faltering in speech.
A dash sets off a parenthetical element for emphasis or (if it contains commas) for clarity.
Parentheses set off nonessential matter and enclose numerals or letters used for lists.
If you guessed Mr. Goodrid
Then you all get a homework pass!
(Only good on saturdays and sundays)
Square brackets set off additions or alterations to quoted matter and replace parentheses within parentheses
Ellipsis points indicate an omission from a quoted passage or relective pause or hesitation
Ellipsis points mark an omission within a quoted passage
The slash is used to mark line divisions in quoted poetry and between terms to indicate that either term is applicable
If you guessed Mrs. Swihart
You are just awesome!
In a high school far, far away. . . .
Episode 1
English 101
We have been faced with a task of the utmost importance.
To tell the world of proper grammar use!
This task was not easy; it took some time. . . but we did it!
We have traveled through the galaxies, searching the unknown.
Braving the elements and discovering exotic alien lifeforms.
We are proud to say. . .
The end.